http://www.dynamicdrive.com/dynamicindex1/ddtabmenu.htm
I found this script. It solves a lot of problems I am facing on drop down menu etc. It just like amazon style tab menu. But it has a problem. If in firefox, if I put more contents as "the second level content", it will overlap with the regular page content.
In their sample, they only give one line second level content, so it seems fine both for firefox and internet explorer.
Forget it! I just found out that was not exactly a tab menu. Actually it was tag content page. Not exactly what I was looking for.