An update to the Android Market bringing it up to version 3.3.12 surfaced late Friday night. This version seems to be an incremental update to the previously available 3.3.11 - in fact, we're not really sure what exactly changed between the two. A cursory run through all the menus didn't yield any obvious additions, although these improvements could be all under-the-hood.
My initial thought was it's somehow related to the Music announcement, but since the Music tab started showing up without any Market updates in 3.3.11, it must be something else. The only hint on the entire Internet comes from T-Mobile which insists you will need 3.3.12 in order to see the free songs every week, but I am skeptical.