First off, just relax. Not the end of the world for you or your scaly friends...if treated properly.
Take out everything from their enclosures. I threw everything away except the water bowl (which may have been a bit drastic, but effective). Take out whatever substrate you have and clean the entire enclosure (I used a new natural non-toxicWindex i found at the grocery store). Put newspaper down. Purchase some cheap mite killer from the pet store while you are waiting for the Provent-A-Mite to come. THe store bought stuff will work for about an hour then you will see mites start to reappear. I got mine off ebay and it was here in 2-3days. Spray the entire enclosure with the PAM including the newspapers, Let everything dry. Follow directions on can (duh). It may take a few days for all the mites to die after spraying the PAM (I think my pam was 100% effective after about 2-4 days. Try not to handle our snakes too much due to mite related stress. I would leave the newspaper in for about a week after you've seen the last live mite. This may be overkill, but i think it is a good way to make sure they are gone for good. Once you've re-introduced new substrate/hides etc, i would spray them all with PAM before you put them in the enclosure to add the extra level of protection. ESPECIALLY the substrate, that seems to be mite hold-out headquarters.
P.S. Some may tell you to take your snakes to the vet to get an ivormectin (Spelling?) treatment. I think that is (1) a waste of money, (2) Unnecessary if you are using PAM (3) Did i mention a waste of money? My vet wanted to charge upwards of $150 PER snake, dont think so Mr. Vet, i've got PAM!