Sauna?

Does anyone use a sauna for health benefits?  My gym has a sauna and a steam room....and I've heard that regular use of a sauna helps reduce the levels of toxins in the body, and actually helps temporarily speed up your metabolism....at least thats what I've turned up in my research... can someone give me a tip on how to use one?  Do i throw water on the rocks?  how often?  How long do I sit in there?  Do i lay down or sit down?  Any tips would be helpful. Scott