Google ( GOOG) and Comcast ( CMCSA) are in "serious discussions" about buying a minority stake in Time Warner's ( TWX) America Online, The Wall Street Journal reported. Citing people familiar with the situation, the paper said the talks focus on AOL's Web portal, not its fast-eroding dial-up Internet access business. The deal would value AOL around $20 billion, the report said, noting that any bid would be worth considerably less because the dial-up operation is responsible for the vast majority of AOL's cash generation. The news comes as the Internet business undergoes a huge metamorphosis. AOL, whose parent is under pressure from restive shareholder Carl Icahn, has previously been reported talking to Microsoft ( MSFT) over a possible combination of AOL with the MSN online service. On Wednesday, Microsoft and Yahoo! ( YHOO) agreed to allow interconnection of their also-ran instant messaging systems. And last month eBay ( EBAY) branched into voice over Internet protocol phone service with its $2.6 billion agreement to buy Skype.