The new Android OS will provide USB Tethering and better support for flash. Users will be able to update all applications in a single click and also have the option to store apps on SD.
Android 2.2 will be released sometime in June and may take longer to appear on phones but HTC has said any 2010 phone such as the Desire, Droid etc will have the update during the second half of this year.
More information can seen in the videos below
Great keynote speech from this year's Google I/O Conference
Introduction to Android 2.2
Google Apps can be taked to Google TV
UPDATE
According to Android Community Froyo or Android 2.2 is now appearing on some lucky Nexus One Owners. All Nexus One owners will receive the update OTA (Over-The-Air) later this year, However HTC Desire Owners (Which I am one of them) will have to wait until late September or October 2010 due to HTC need to verify and customize it to their needs.