^The Control + Tab doesn't work for me, either be it Safari 3 or Safari 4.
To the OP: You can set keyboard shortcuts via System Preferences > Keyboard & Mouse > Keyboard Shortcuts.
Just add a new short cut for
Select Previous Tab and
Select Next Tab and you're set.
PS: With MultiClutch (to configure three-finger gestures) I set those shortcuts to
rotate left and
rotate right.