Irrefutable proof of the linkage between Saddam Hussein and Osama bin Laden on Friday, when The Don, Defense Secretary Rumsfeld, repeatedly got the two mixed up during a National Press Club luncheon in Washington.

Here's a couple of quotes from the transcript published by the US Department of Defence on their website. Exhibit A:

But if you think about it, that's not the way the world really was before September 11th. Consider the world of September 10th and before. Two Americans and six others stood on trial by the Taliban in Afghanistan for the crime of preaching their religion. The leader of the opposition Northern Alliance, Massoud, lay dead, his murder ordered by Saddam Hussein -- by Osama bin Laden, Taliban's co- conspirator.

Exhibit B:

Saddam Hussein (sic), if he's alive, is spending a whale of a lot of time trying to not get caught. And we've not seen him on a video since 2001. Now he's got to be busy. Why is he busy? It's because of the pressure that's being put on him.
...
DONNELLY [John Donnelly, chair of the luncheon]: Mr. Secretary, you said earlier that Saddam Hussein hasn't done a video for a while. You meant Osama bin Laden, right?

RUMSFELD: I did. I meant that we haven't seen Osama bin Laden. Thank you.

The 52-minute video of the speech is available on the C-Span website for the next couple of weeks.

Recommended further reading:
The Poetry of DH Rumsfeld - Hart Seely, Slate, 2 April 2003.
Transcript, Dept of Defense news briefing, 12 Feb 2002: The Don's immortal "known unknowns" speech.