A week after a Wall Street analyst floated the idea of a Microsoft acquisition of Yahoo!, the two companies' instant messaging programs are getting together.

Yahoo! notified its IM users that a forthcoming feature will allow them to message with users of Microsoft's newly launched Windows Live Messenger (formerly MSN). The feature is listed under "coming soon" on Yahoo's IM home page.

The two companies said in October they would link their IM systems, creating an expected base of more than 275 million users. Microsoft currently has about 240 million active users. The ability to message across the two systems is one of the most-requested features, the companies said at the time.

The plan last fall was to roll out the feature in the second quarter of this year, which ends Friday. Neither company would be more specific about a release date.