IE6 now has tabbed browsing if you use the new MSN Toolbar. Been messing with it since last night, so far so good. Nothing new or great but at least it now has tabbed browsing. 
It will take a lot more than tabbed browsing to make me go back to IE as my default browser, before firefox (primary) and avant (secondary).
Even when IE7 comes along it will get installed just to reduce any exploits because it is an integral part of the OS.
Max,
You’ll find many alternative Tabbed Browsers on My Server.
Just take a look HERE.
Except for FireFox, they are all IE based with many features.
did anyone tried this tabbed browsing? it seems there is no button for it ??? :