different sites are reporting "Update goes live,now available for download"
obtain the update by heading over to Menu > Settings > System updates > and clicking on the HTC software update command. You’ll then be able to download the update over-the-air. You may need to reboot the device to complete the upgrade.
edit: just tried on my phone and no update available for me.
sources came from the following.
android community-
HTC EVO 4G receives general Software update | Android Community
The Androider -
The Androider
Erictric -
Software Update For HTC EVO 4G Goes Live, Available For Download