Take a look at the tiddler linked to from the community wiki:
http://tiddlywiki.com/#TabMacro
The syntax used there, with macro parameters explained in brackets:
<<tabs txtFavourite[cookie]
One[label1] "First tab"[tooltip1] HelloThere[tiddler1]
Two[label2] "Second tab"[tooltip2] ThankYou[tiddler2]
>>
HTH.
-- F.