SAN FRANCISCO --

Apple

(AAPL) - Get Report

appears ready to follow through on plans to launch the iPhone in Europe this quarter.

As reported by

Reuters

, the company has scheduled a press conference in London on Tuesday, fueling speculation that it will soon make the iPhone available in Europe's largest consumer markets. Apple is likely to discuss which local telecom carriers will provide service for the iPhone, and when customers will be able to buy it.

Shares of Apple were recently up 85 cents to $137.70.

Reports have swirled for months that Apple is working with telecom carriers in the continent's largest markets of France, Germany and the U.K. The likely suspects include O2 UK, a subsidiary of Spain's

Telefonica

,

Deutsche Telekom's

(DT) - Get Report

T-Mobile, and

France Telecom's

(FTE)

Orange.

A bigger question is whether a European iPhone will operate on the faster 3G networks that are common in Europe. In the U.S., the iPhone runs on

AT&T's

(T) - Get Report

slower Edge network. Analysts have said that

TST Recommends

a 3G phone might not be available in the U.S. until after the holiday season.

"Having a phone operate on a 3G network is much more important in Europe than in the U.S.," says Darren Chervitz, director of research for the Jacob Internet fund, which owns Apple shares. "Europeans are much more mature in their usage of data services and the state of their networks."

Without a 3G version, Apple may find itself at a loss in drawing customers away from local cell-phone giants such as

Nokia

(NOK) - Get Report

, the world's largest cell-phone maker, as well as

Sony Ericsson

, a joint venture between

Sony

(SNE) - Get Report

and

Ericsson

(ERIC) - Get Report

. These companies hold just a sliver of the U.S. market but are dominant in Europe.

Since the beginning of the year, Nokia, for one, has shipped several multimedia phones in Europe that offer Internet surfing and navigation, music playing and video recording.

But Apple products are gaining popularity in Europe as the company opens stores across the continent. Sales of the company's iPod portable music player and songs from its iTunes online music store have also gone a long way in introducing consumers to Apple.

iTunes is available in the local languages of roughly two dozen countries across the world, including many European markets where cell phones have been ubiquitous for years.

The cell-phone market, however, is unlike other markets in which Apple operates. The company's iMacs are much more distinct than competing personal computers, and no digital music device rivals the iPod. But there many established players in the cell-phone market and an even greater number of alternatives to the iPhone.

What's more, prices on cell phones fall much faster than on products in other segments of the tech sector.

"We are very much beginners at this, and so every day there is something to learn," said Apple's finance chief Peter Oppenheimer, referring to the cell-phone market during the company's last conference call.

Apple learned a big lesson when it outraged customers by slashing iPhone prices just two months after the device debuted. Similar gaffes may leave it more bruised in the hyper-competitive European cell-phone market.