Microsoft is reportedly in talks with Time-Warner to buy a stake in AOL and merger the online giant with its own MSN service.

The New York Post reported this morning that it has learned of the talks from two sources. According to the Post, MSN and Time-Warner would jointly own the merged service as equal partners.

Spokespeople for both Microsoft and Time-Warner have declined to comment on the Post’s report.

Time-Warner shares surged upwards on the news. The company has been under pressure from investor Carl Icahn, who is reported to be buying up shares and putting pressure on Time-Warner CEO Richard Parsons to take action to increase their price. Time Warner earlier this year set aside $3 billion to settle shareholder lawsuits over the merger with AOL.

AOL’s subscription growth fell four percent in the most recent quarter but the company still has a reported 20.8 million subscribers. Both AOL and MSN have been under pressure from Yahoo! and Google, and now from eBay as well, with its purchase of Skype. Yahoo! is the Internet’s most visited site and is partnered with two major telcos, SBC Communications and now Verizon, in developing content portals for their broadband services. Google, the most popular Internet search engine, is rapidly expanding its reach, most recently into VoIP with GoogleTalk.

AOL launched its own VoIP service last April, while Microsoft bought its way into VoIP with the recent acquisition of Teleo. How a merged MSN-AOL would function in the VoIP world, competing with eBay-Skype, Google, Yahoo! and others, isn’t yet apparent.