regularly goes in search of the best rates for various banking products. Today's focus is on 15-year fixed-rate mortgages.

The mortgage giant Freddie Mac ( FRE)announced this week that mortgage rates fell...again.

Rates tumbled for the fourth straight week, according to Freddie Mac's primary mortgage market survey results. The news comes as no surprise. The seemingly endless stream of bad economic news and the Fed's big 75 basis-point cut in the overnight rate all but guaranteed the mortgage rates would fall again this week. (A basis point is one hundredth of a percentage point.)

So -- for those lucky enough to hold a conventional mortgage -- is it time to refinance? Have we hit the bottom?

Not likely, says Philip van Doorn, an analyst at Ratings. "Liquidity is still pretty tight," says van Doorn. As the markets come down, he says, they'll be more liquidity, which will push rates farther down.

"That's why personally, I'm going to wait another three or six months and then try to refinance," van Dorn says.

But if you are in a hurry to refinance, consider getting a 15-year fixed rate mortgage (FRM), as opposed to a 30-year FRM. Though you'll be paying more each month, there's a double benefit, Van Dorn says. You'll be building equity faster and your mortgage rate will be lower. And you might not be paying as much more as you think: In the past two weeks, the difference between 30-year and 15-year FRMs has been bigger than it's been since the end of 2005.

So for those of you considering refinancing with a 15-year FRM, we searched around for rates on . In all cases, it's necessary to check with institution for further terms and conditions. Normally a 20% down payment is required. Rates are typically based on $175,000 financed for purchase of single-family, owner-occupied residence.

All rates have been updated on or after Jan. 18. More mortgage rates are available here. .

Here are the highlights:

  • Internet banks Mortgage Integrity, EverBank, Hills Mortgage & Finance Co., and Affinity Mortgage Services all are offering rates below 5% in many states.
  • Astoria Federal Savings & Loan Association and Sovereign Bank (SOV) offer rates in New York as low as 5.125%.
  • Wachovia Bank (WB), National Association offers a 15-year FRM in Texas at 4.375%, one in New York at 4.625 and one in Florida at 4.750%.
  • Central Illinois Bank offers 5.125% rates in Illinois.
  • Seacoast National Bank (SBCF)offers 5.125% rates in Florida.
  • In Virginia Wells Fargo Home Mortgage (WFC), Chevy Chase Bank and National Bank of Blacksburg all offer rates of 5% or less.
  • Elsewhere, here's a look at the national averages for loan rates on various types of mortgages:

    To search for local rates on mortgages, click here.