Ivermectin is one option. I am unfamilair with the procedures surrounding the use of this so I won't comment.
Nix is an excellent treatment and probably one of the safest methods. Diltue 1- 4 oz bottle to 1 gallon of water and spray snake and enclosure, repeat again in a week, then after that in 2 weeks.
Provent-A-Mite is a tried and true method, though if not followed exactly as follwoed the results can be lethal. There have been many deaths resulting from improper use of the product.
Black Knight is another tried and true product, which is also quite safe for the snake. Spray all over snake and enclosure. The stuff is so potent it will kill all the bugs in the room so be careful if you keep any invertabrates.
Vapona is an old method and if you choose to go this method be VERY careful as it is a very toxic chemical. Place a small peice in a small ventilated container so the snake cannot make contact with it and change periodically. And as PoiSoNouS mentioned, the water eneds to be changed frequently.
For some great info on mites, check out this page:
<a href="http://vpi.com/9VPITipsAndTechs/TheWarAgainstSnakeMites/TheWarAgainstSnakeMites.htm">The War on Mites</a>
Good lcuk with your battle