Is there a toolbar for Internet Explorer that can perform tabbed browsing?

Try and look for a FREE toolbar. Not a toolbar that contains AD-AWARE or SPYWARE either!

Is there a toolbar for Internet Explorer that can perform tabbed browsing?virus scanner

Yes, although it has not been advertised (most likely because it is not as smooth as Firefox), the current MSN Search Toolbar for Internet Explorer offers the option to use a tabbed interface.

Is there a toolbar for Internet Explorer that can perform tabbed browsing?anti virus software

No. However, you can download the Firefox internet browser. Totally free, no spyware, no adware, faster, more effective, extendable, skinnable, and it supports tabs. http://www.getfirefox.com.
Better than a toolbar, why don't you try http://www.maxthon.com/

It uses the IE browser engine AND has tabbed browsing.
No, not IE-6. Tabbed browsing is in IE-7 which you can have free now but it is still in beta %26 runs a little slow.

Firefox has it but Firefox doesn't handle active X so lots of web sites don't display right.

Hang in there IE 7 will be ready soon.
IE Beta 7 has it. Just get Firefox, faster and tabbed browsing and faster.