Yes you can turn it off, by I usually suggest people leave it on. It really only kicks in if there was a blue screen. That data is uploaded (after it asks for your permission) to MS who sorts them into 'similar' buckets trying to find the guilty driver. They then forward those crash dumps to the various software makers (they really do, we've got some folks that spend their time analyzing them once we see them from MS). Think of it as a distributed effort to make drivers more resiliant, so it turns out to be good for you and for others (you just may not see the benefits immeidately, but the program has dramatically improved driver stability on XP since it's initial release)
Bill