John,
I wouldn't panic if you don't have a fan in your nursery. To be honest, whatever else is going on in the room, the biggest factor in SIDS, in my understanding is smoking. I read the article again, but I don't see any indication of types of fans...it seemed to imply that it was just important the air was circulating. When I read it, I assumed it meant ceiling fans, but now that I read it again, I don't see that at all. My best guess would be that anything that circulates the air fairly well would serve the purpose it is talking about. Again, I really don't think this is the sort of thing where you need to run out and get one tonight or your baby will succumb to SIDS!
Nicki :-)