Strategy Page says yes:

The American invasion of Iraq in 2003 would appear to have been a plus for al Qaeda, as Saddam Hussein, and his Baath Party, had long been an enemy of Islamic radicalism. But Saddam got religion after his defeat in the 1991 Gulf War. During the 1990s, Saddam became a major supporter of Islam, building many mosques and proclaiming himself a major defender of the faith. Al Qaeda was wary of this, but did enter into negotiations with Saddam. After all, Saddam and al Qaeda shared a hatred for the West, and especially the United States. A major fear was that Saddam would provide a refuge for al Qaeda, and supply them with chemical or nuclear weapons (if not a bomb, then radioactive material.) The fighting in Iraq is basically between the Sunni Arab minority, assisted by al Qaeda, against the majority Kurds and Shia Arabs. While much is made about Iraq becoming a “school for terrorists,” few of the “graduates” have shown up anywhere else, pulling off successful attacks. On the other hand, many known Islamic terrorists have gone to Iraq, and gotten themselves killed or captured. So Iraq has to be seen as a net loss for al Qaeda.