Regarding Exchange and the Droid 2.2 Froyo update.
Some users have been experiencing problems with the HTC Droid 2.2 update and Exchange. HTC support suggests this method for correcting the sync issue.
From HTC:
With the error you are receiving on your device with your Exchange Server you will need to first delete the Exchange Account again > then you will need to Clear Calendar and Calendar storage (Menu --> Settings --> Applications --> Manage applications). After this is complete you will need to reboot your phone and then try to add the Exchange Server Again and see if the issue persists.
We do not have an HTC phone in our area with this update, so I cannot directly confirm these instructions. I have heard from the faculty member that it appears to work.
Android