The Android 2.3 source code is now available for manufacturers to be ported onto their devices. The Android 2.3 Gingerbread handles memory and power better than 2.2 Froyo which means that we can hope Gingerbread to be ported very soon to many more devices in the near future. You can also expect an Android 2.3 update very soon.
Any device that runs well with Froyo should run even better with Gingerbread. The base hardware requirements have not changed. Of course OEM updates do depend on individual OEM efforts, and I can’t speak for the OEMs, but there’s no technical reason devices able to run Froyo shouldn’t be upgradeable. I think the Froyo->Gingerbread migration should be less painful for device developers than Cupcake->Donut or Eclair->Froyo.
Based on what we have seen, Android 2.3 should be able to run on most devices and I expect it will be coming to every phone that currently runs Android 2.2 (or those that are getting it soon like the Galaxy S).
We will update, when Gingerbread starts flowing out to the phones. Check out our other posts before leaving!