A recent Knight-Ridder investigation concluded:

The administration’s case on ties between Saddam Hussein and al Qaeda relied on intelligence that was weaker than that on Iraq’s illegal weapons programs.

The article linked above discusses some of the "evidence" that has been paraded about (here and elsewhere) purporting to show the alleged connection between Iraq and al Qaeda.

Yes, this too, like the (lack of) WMDs, will be an election issue.