We documented it right here on FR in 2003:
http://www.freerepublic.com/focus/f-news/1008415/posts
Iran, Saddam, & Osama: A Continued Report
Compiled By: Ryan Mauro
IRAN
This is the second continuation of my original report on Irans alliance with Osama Bin Laden, which was titled, Iran and Bin Laden: A Match Made in Hell. My follow-up report simply listed the names of high-level Al-Qaeda leadership congregating in Iran with complete safety. It was named Al-Qaeda Leadership in Iran. Readers should look at those two articles before viewing this report.
More at link above:
The new head of Al Queda was under Iran control until last year.