Looks like AT&T are on a roll. After releasing an update to enable HSUPA for the Atrix 4G it seems the Inspire 4G is getting the same treatment. It is an over the air update so if you haven't received the update yet then be patient. Or if you don't wish to be patient then you can check out HTC's support page and just do it manually.
The update will also enhance Windows Live email. If anyone has got the email be sure to tell us if anything else is improved after the update.