Although Sprint announced yesterday that the much-anticipated Android 2.2 update for the HTC EVO 4G will be released next Tuesday (August 3rd), the fact that users are also being allowed to initiate the update themselves (rather than wait for it to be pushed to their handsets) means that the "Check now" button in Menu -> Settings -> System updates -> HTC software update is probably taking quite a bit of abuse today. Previously leaked information indicated that the upgrade could be released as early as today, so of course many people are trying to see if it's available to them.
There have been no reports of proven success just yet, but G&E reader Charles S noticed that the new update is already listed on Sprint's EVO software page as having been released today. Version 3.26.651.3 has all the enhancements characteristic of Froyo, not to mention the other EVO-specific goodies, and is a significant jump from the previous update (version 1.47.651.1), so there's no doubt that this is the update.
Keep mashing that "Check now" button, folks. You won't see "There are no updates available for your phone" forever!