Hey guys, I got tired of waiting so I did the goldcard-ruu update posted here. It's really easy. Theres a tool tool to make you a goldcard, then its really only a few clicks. I got the latest .EXE for HTC Desire RUU (world wide english) and it went without a hitch. I did 3 more of my co-workers today using WinXP, Win7 (32) and a Win7 64bit.
All you need is the Sync 3.0 installed, make a goldcard, then run that .EXE and sit back for 5 minutes.
I did have issues on a pc where I had to use the rear USB port to get SYNC to see the phone, and on one Win7 machine it just wouldnt keep connected so I did it on a XP box. One of the phones crapped out halfway (power issue with the crappy usb bay) and the phone was stuck in a boot-loader type mode. Just took out the battery and redid it and all was fine, so I think theres no real danger here if you follow the guide as I've probably had the worst happen.
I can verify 2.2 runs quicker and does have some nicer features. Web browsing and looking at flash is waaay better. Can't say battery lasts longer though but I havnt put it down since I did the upgrade!
EDIT: The only thing I did differently from the guide was I used the newer RUU mentioned a bit later in the thread, the one ending with .....142828.exe, its the latest according to the site.
Theres also mention that you need unrevoked for something, but you dont need that, nor do you need to root your phone for this.
http://androidforums.com/htc-desire/148932-froyo-ruu-update-available.html