On this morning's Today show, Matt Lauer teased that Katie Couric would be showing up tomorrow to make a "major announcement."

Whatever could it be?!?!

That she's leaving the CBS Evening News? That she's returning to the Today show? That she regrets ever leaving her morning perch? That these three possibilities are not mutually exclusive?

Or how about one rumor we've been hearing that involves Katie and a certain blue-eyed anchor?

Industry chatter that reached us over the weekend spoke of the possibility that Couric and Anderson Cooper are set to swap jobs, with Couric heading to CNN and Cooper taking over CBS's evening braodcast.

Evidence there's a decent chance this will play out: CBS and CNN have long discussed merging their news operations in one form or another, the most likely scenario being CNN to take over much of CBS News' role, but with the tiffany network keeping its evening news program.

Evidence there's a decent chance this is nothing more than a rumor: Why would Katie return to her old haunt on NBC to make the big announcement? While Today will benefit from a ratings surge tomorrow morning, NBC doesn't have much interest in promoting big developments at either CBS or CNN.

* Update: Reports Drudge: "SOURCE: NBC, CBS, and ABC jointly hosting cancer research telethon. Couric to announce on NBC's TODAY SHOW tomorrow… Developing…"