Hard to say. I'm kinda wondering why they haven't attacked here again yet.
The ongoing War on Terror must be having some impact, though how much is hard to say. We have captured lots of their guys, and undoubtedly even more are constantly on the run or in hiding and unable to communicate well.
The Olympics might not be a juicy enough target for them right now. Too much security, too many "allies" to offend. I'd expect them to direct what resources they have to attacking targets clearly identified with the War on Terror, like the US and England.
They're probably directing a lot of resources against our forces in Iraq, but they're well-prepared, and terrorists can only get one or two guys at a time, if they're lucky. It's hard to say if they have the resources left for a major attack in our homeland. No choice but to stay vigilant, and wait and see.