Yahoo Inc. has became the latest potential suitor for America Online, joining Google Inc. and Microsoft Corp. in what may soon turn into a bidding war for the Internet service.

The talks between Yahoo and AOL's parent company, Time Warner Inc., are at an early stage and have involved the exchange of basic information, sources said. Both Microsoft and Google are further along in their negotiations with Time Warner, according to people familiar with the situation who spoke on the condition of anonymity because of the confidential nature of discussions.

Corporate financier Carl C. Icahn — who is pressing Time Warner to take action to boost its stock price — said in an interview Friday that selling a stake in AOL was positive, provided the giant media company uses the cash to help pay for a $20 billion stock buyback. Icahn also wants Time Warner to sell or spin off to shareholders its cable systems unit.

"Doing this AOL deal is on the way, but not enough, to enhancing shareholder value at Time Warner," said Icahn, who heads an investor group that owns about 3 percent of the company. "It proves my point that there is a great deal of unrealized value here. The best investment the company can make is in their own stock at this time."

Time Warner stock has been flat for some time, trading around $16 to $17 a share.

The jockeying by suitors marks another sharp turn in AOL's fortunes. In the late 1990s, AOL was the top online gateway for Americans getting acquainted with the Internet. But as speedy broadband service became more popular than AOL's slower dial-up access, AOL began losing subscribers, and within a few years of its 2001 merger with Time Warner, the service was widely viewed as a dinosaur.

But AOL still commands a large customer base and is refashioning itself as a free site. The newly intense interest in the Internet service provider began after Microsoft proposed that its MSN search engine replace Google on AOL. In addition, Microsoft would put cash into the deal and combine its MSN service with America Online.

Scott Kessler, an analyst with Standard and Poor's, compared the jockeying over AOL with what happens when a number of people become interested in buying the same house. Even though it may have defects — and in AOL's case, a shrinking dial-up subscriber base — it also has attributes, including its extremely popular AIM instant messaging service. AIM users are viewed as potentially lucrative targets for online advertising and various Internet services such as music.

A combination of AOL and Yahoo could pose antitrust objections from federal regulators because Yahoo, with hundreds of millions of registered e-mail users, and AOL are two of the most heavily trafficked Internet services, as measured by comScore Media Metrix.