We already know that Samsung is prepping an update for the US Galaxy Tab 10.1 that includes the new Touchwiz UX interface, but if you just can't wait to get your hands on it, then LevitateJay over at the XDA Forums has the solution for you.
Even though we're still waiting to see Touchwiz UX here in America, the Italian version of the Tab 10.1 is already shipping with it intact. So, what do we do when a one device has something that another doesn't? Wait for XDA to port it of course! That's exactly what has happened in this scenario, as Jay found a way to extract Touchwiz UX in its entirety from the Italian Tab 10.1 and made it available via flashable ZIP or Odin for all other variants of the Tab.
Unfortunately, there are some issues with this build since it was originally designed for 3G equipped tablets: the email app doesn't sync (Gmail works fine), Samsung Apps won't start since there is no SIM card in the WiFi Tab, and possibly more.
If you think you can handle that, head over the source thread at XDA for full instructions and downloads.