For Vista and 7 users
ATI late yesterday appears to have released an update for their new HD 5800 series cards, running under Windows Vista or 7 in 32/64-bit editions.
No release notes are included as such, but naturally it's recommended to grab these for the latest improvements; hit the source for the new package.
As always, uninstall the old set and use a cleaning program like the free Driver Sweeper before installing the new.
For the rest of us, ATI says we can expect the 9.10 drivers when Windows 7 launches -- October 22.