Yup, I just installed Android 2.2 Froyo on my Nexus One. Since I don’t have stock Nexus One rom anymore (but was running HTC Desire ROM), I had to update the phone manually.
Modaco, one of the famous Nexus One hackers, put the image of Froyo Android 2.2 for those of you on Cyanogen or HTC Desire ROM.
The install took me about 5 minutes max, all you have to do is download the new image files then install it using the Bootloader.
For full instructions, head over to our Nexus One Hacks blog!
I will have a full video hands-on review of the Froyo Android 2.2 soon, working on it right now!