Microsoft this afternoon took down most of its Zune online system for maintenance, including the Marketplace and the web, ahead of the launch of the Zune HD and its accompanying new PC software. The update involves a pre-planned but major revamp of the underlying service and won't see the service go live until the "early hours" of the 15th, just before the hardware and software updates are available.

The company still hasn't said what the new Zune services will involve, though it's known that HD movies are coming to the Zune Marketplace to take advantage of the Zune HD's 720p playback. It's also accepted that the Zune HD should have a third-party app platform and will likely have deeper integration of the Social component.

Simultaneously, Dell has already started discounting the Zune HD before its release and has begun a one-day pre-order sale that sells both the 16GB model for $187, down from $220, and the 32GB model for $247, down from $290. Dell hasn't given a particular reason for the discount but regularly uses sales during launches to spur early orders.

Stay tuned to Electronista for a look at the Zune HD early tomorrow.