HTC has finally released the free Windows Mobile 6 upgrade for the HTC S620. The much-anticipated upgrade also includes Yahoo! Go but is missing Office Mobile (Instead, it comes with the Clearvue applications).
The download is free from the HTC e-Club (membership required though) but you must register your S620 to be able to download the upgrade.
Note: The update will replace the current ROM image and will erase partnership and all user data and programs on your device. Be sure to back everything up before you start.