yeah thats really useful, i use it almost everytime i'm on the net. My brother who is a windows user uses mozilla now and loves tabbed browsing after seeing it on my mac. But he can't switch between tabs like i can (i don't think) and he thought it was very cool, and now its something he misses and wishes was there!
anyway the main reason i posted was because i have a wireless intellimouse explorer 2, which has 2 spare "wing" buttons on one side, i couldn't decide what to use them for so i made one switch to the next tab and one close the current tab/window. How cool is that? now i dont have to move or use the keyboard to close tabs or move on to the next thing i'm reading.
also when in any other program i use them to trigger expose, one to zoom back on all the windows and the other to show the desktop, it saves me so much time!
just thought i'd let you guys know how i do it here in the UK, sometimes you don't think of something until someone mentions it?