Gas is getting close to $3 a gallon or more, and in part it is because of attacks on Nigeria's oil infrastructure, said Jim Cramer on his "RealMoney" radio show Monday.

Rebel groups are influencing the price of oil by fighting Nigeria's military, kidnapping workers and blowing up oil facilities, he said.

Supply is tight, and oil facilities are easy targets, Cramer added, making it the "perfect storm" for higher oil prices.

There are also threats on oil pipelines in Iraq and Iran, but he is focusing on Nigeria because it is the world's fifth-largest oil producer.

If you take out Nigeria, prices will spike, Cramer said.

When you read about problems in Nigeria, he believes that the play is Willbros Group ( WG).

Cramer called the company the antidote to pipeline blowups because it is Willbros' job to rebuild pipelines as they are blown up, and it looks like that will be a steady stream of work.

He said that Willbros is the speculative play, and that Schlumberger ( SLB - Get Report) is the nonspeculative, blue-chip play on unrest in Nigeria.

He said the French company is the largest oil-services company in the world and now that the stock has split, that's an opportunity to buy.

If you held a share of Schlumberger at $130 last week, it looks like your stock dropped to $65. However, it really means that you now have two shares worth $65 a piece.

While there's no real increase in the company's valuation, it makes it easier to buy, he said.

Cramer likes the company because companies that want to drill anywhere in the world have to hire people to do it.

And Schlumberger is the company they call when they want to drill, he said, because it provides technology, project management and information solutions.

Cramer's Callers

A caller wanted to know what to do about UnitedHealth Group ( UNH - Get Report), which has fallen steadily from nearly $65 since December.

Cramer said that he likes the nation's largest health maintenance organization, which he owns for his ActionAlerts PLUS charitable trust portfolio, even though its declines have accelerated.

He said that this has happened for three reasons. The first is rotation, meaning that the health care sector is out of favor on Wall Street and that sectors such as the minerals are better liked.

This doesn't mean that there's anything wrong with the stock. It just means that the sector is out of favor but that the rotation will shift and that health care will be liked again someday.

Some investors have also worried that the company has made too many acquisitions, but he said this doesn't bother him because he believes that these decisions will pay off once Medicaid Part D takes off.

Finally, Cramer said that the stock has most recently taken a hit on worries that CEO William McGuire may have done something unethical by giving himself lots of stock options before the company made big moves higher.

As to whether McGuire was overpaid, Cramer would not say. He did point out that for five years the company was the No. 1 performing stock in the U.S.

Cramer added that he's not throwing in the towel because UnitedHealth is a good, quality company that trades at a low P/E ratio. Plus, he said that most of the company's woes will eventually end.

Cramer told a caller that there is a way to play the construction boom. He reminded the caller that housing construction will likely slow as the Federal Reserve continues to raise interest rates and that commercial construction "can still have its day."

He also believes that there is money to be made in road repair and construction.

The company he likes is Caterpillar ( CAT - Get Report), which is up 31% year to date.

He said it's by far the best large-cap equipment machinery company in the world.

He also likes Ingersoll-Rand ( IR - Get Report) and Kubota ( KUB).

Cramer congratulated a caller for the way she played Pacific Ethanol ( PEIX - Get Report), which is up 50% year-on-year.

The caller took a third of her position off when the stock ran higher, and Cramer said that if she takes half of her remaining shares off at this point, she'll be left with only "the house's" money on the table.

He also told a caller not to worry about the "healthy pullback" in Mindspeed Technologies ( MSPD).

It is part of a group of tech companies that have had a "remarkable resurgence" because they are involved in the fiber-to-premise rollout.

This means that they are part of the switch from copper to fiber in our phone lines, which will allow telephone companies to deliver services like video on demand.

Cramer believes that this implementation is nowhere near complete and that buyers should use this pullback as an opportunity to buy more shares.

Mousing Around

A caller said that his wife has owned Disney ( DIS - Get Report) since 1965, through many ups and downs, and wanted Cramer's opinion on the stock.

Cramer said that it's not his favorite stock, but now that it has made the decision to put its programming on the Web, he likes it more.

Bob Iger now runs the company, and Cramer said that Iger is a well-liked team builder who is leading Disney through a major turnaround. It's still not his favorite stock, but Cramer said it was all right to own it.

Disney and ABC are making their most popular programming free online. Viewers will be able to pause, forward and rewind shows, but they will not be able to skip the embedded commercials.

Ford ( F - Get Report) and Procter & Gamble ( PG - Get Report), which is another stock Cramer owns for his charitable trust, are among the companies that have signed on; but Cramer said that these companies are not where the big money will be made.

Instead, he said to take a look at Akamai Technologies ( AKAM), which makes the technology that allows consumers to stream video onto their PCs.

He also said that Akamai teaches investors a lesson in pain and patience. Cramer said the stock has seen a 140% return over the year, but some people are complaining because it has dropped a few points from its 52-week high hit on April 3.

The stock lost value over the last week or two, but it's still a good investment, he said.

For investors who listened to his recommendation back in November, did their homework and bought the stock, they saw it jump from $17 to $30.

Now it's down $3 since the beginning of April, a drop that some people can't handle.

If you can't stand to see a high-flying stock come down in this way, Cramer said that's okay.

One way to deal with these large shifts can be to have this type of stock be only a small portion of your overall portfolio. Then, he said that diversification will cushion some of the bigger falls.

Or, Cramer said, just don't own a stock like this at all. "There are other ways to make money," he said.

Cramer believes that there is money to be made in the host of new cell-phone innovations that are hitting the market.

The New York Times recently reported that cable companies are developing wireless products that allow customers to program their DVRs from cell phones; and USA Today reported that new UMA (unlicensed mobile access) technology will allow cell-phone users to make phone calls at wireless hotspots.

Cramer said that it's time to start thinking about Openwave ( OPWV) and that he'd give listeners more on this stock later this week on his "RealMoney Radio" show.

Here's your chance to pick the stock you'd like me to feature on my radio show April 13:
Akamai Technologies
Brush Wellman
Crystallex
Goldman Sachs
National Beverage
Tom Online

REMEMBER to listen in on Thursday for my take on the stock that wins this poll!

At the time of publication, Cramer was long UnitedHealth Group and Procter & Gamble.

James J. Cramer is a director and co-founder of TheStreet.com. He contributes daily market commentary for TheStreet.com's sites and serves as an adviser to the company's CEO. Outside contributing columnists for TheStreet.com and RealMoney.com, including Cramer, may, from time to time, write about stocks in which they have a position. In such cases, appropriate disclosure is made. To see his personal portfolio and find out what trades Cramer will make before he makes them, sign up for Action Alerts PLUS. While he cannot provide personalized investment advice or recommendations, he invites you to send comments on his column by clicking here. Listen to Cramer's RealMoney Radio show on your computer; just click here. Watch Cramer on "Mad Money" at 6 p.m. ET weeknights on CNBC. Click here to order Cramer's latest book, "Real Money: Sane Investing in an Insane World," click here to get his second book, "You Got Screwed!" and click here to order Cramer's autobiography, "Confessions of a Street Addict."