If you own the T-Mobile myTouch Fender Limited Edition, don't fret (pun intended). After the original myTouch 3G is all done being served Froyo, the Guitar-centric device and the myTouch 3G Slide will be next on the list to get upgraded.
Those receiving the Android 2.2 upgrade on their T-Mobile myTouch 3G will also get a "new home screen experience, new Exchange e-mail integration and the addition of Faves Gallery". The update will come in two parts sent OTA and you cannot opt out of it. Of course, with support for Adobe Flash among other new features, why would anyone in their right mind want to?
T-Mobile myTouch 3G Specifications | Review