Well, after reading a few of those links it looks like its *possible*, but like I've said I've never heard of it before and I've been in the idustry for 12 years. Belts in dryers are generally nothing special, just a standard FHP belt very similar to what you would have in say, a big garage door opener or even some lawnmowers. I took a quick look through some of my reference on them and none of them state asbestos as material contained in them. Several are coated with cotton or kevlar and will give the belt a "white-ish" appearence, but that has nothing to do with asbestos.
Good of you to look for input before spouting it as gospel. Word of advice: if you hear of anyone or see a website that talks about "flushing toxins" out of your system as some of those websites do, leave.