A big announcement in the digital music space is scheduled for Tuesday morning.

MTV scheduled a conference call for "two industry-leading partners to discuss a new digital music initiative."

MTV is one of the partners. There's a good chance the other one is in the Seattle area.

MTV already has a partnership with Microsoft. It built its Urge music store on Microsoft technology, and Microsoft bundled Urge with the current version of Windows Media Player. Even so, Urge hasn't made a splash -- or a dent in iTunes.

My guess is that MTV and Zune will announce a relationship. Apple fans may chuckle, but there are many reasons a Zune-MTV partnership would make sense.

Microsoft is gearing up to launch several new Zune players and to broaden its marketing beyond hard-core music fans. The next phase of Zune will sure be marketed through MTV and its sister channels such as Comedy Central.

Partisans may think MTV will take a coolness hit by partnering with Zune. But I don't think average consumers would care one way or the other, and MTV would probably like to get whatever boost it can from the big Zune marketing budget.

Zune, meanwhile, could use the credibility that MTV's brand would give the device. Why not let MTV choose the bundle of promotional tunes that come with a Zune?

Maybe it will even put Comedy Central clips on the device instead of obscure music videos.

At a higher level, Microsoft and MTV's parent company, Viacom, are sympathetic. They have similar views on intellectual property protection and Google, and Microsoft has some of the most sophisticated DRM technology available for buying and subscribing to music services.

Further evidence of the corporate sympathies came today when Paramount and DreamWorks announced that they've chosen HD-DVD as their exclusive format for high-definition DVD sales. Viacom produces and distributes Paramount and DreamWorks videos, and HD-DVD is Microsoft's preferred format and includes the Redmond company's software.

Another possibility is that MTV could be turning its back on Microsoft and making a deal with RealNetworks, but that seems like a longshot.

MTV could even be making a deal with a music startup such as iLike. The Seattle social music network service today announced that it reached 10 million users, but MTV probably wouldn't call that industry-leading.