And I had no real issues... other than having to reapply a few widgets on my home screens.
It's great! I wasn't aware that the home screen button and app tray weren't changing on the Droid... but a tipster pointed me to the Helix launcher (find it on marketplace). I installed that and walla! A new home screen with 4 programmable spots for my favorite apps right down there with the home button. AND it gives you up to seven home screens. Now my 2.1 feels complete (even if it is a tiny bit of trickery)
I just tried this and it works!
Says it deletes your user data though.
Wow, 15 Mb for a phone update.
The instructions say to apply update.zip. I picked that and let it wipe the data, then it paused. I had to pick update.zip again.