Three days after the launch of Google Music and the Market's server-side changes, a new version of the Android Market has started to roll out. So far the only change that's visible over version 3.3.11 is the addition of the permission requirement for near field communication (NFC), which allows phones to send data directly to another device nearby.
It does not look like they've changed anything visually or functionally with the Market yet, but this could be the start of being able to use it to pay for non-Market goods via NFC (e.g., swipe your phone at a gas pump, enter a code, paid).
Likely the first things we'll see from this in the Market will be NFC for Google Music purchases: purchase music then transfer a one-time-listen to your friends, but it could also be used to transfer extremely large multiplayer Market games between phones without involving data charges.
As with all Android Market updates, there's no telling when you're going to get it. You can wait and it will probably just update sometime in the future, or you can download the new version from here. It's properly signed by Google, so non-rooted people should have no issues with installing and updating it.