Bath salts, new craze? whats it like?

I'm not talking about the stuff to make your tubbytime nice. I've been hearing of "bathsalts" a lot lately. Could someone whos tried them give me a rundown of what the effects are, doses, best way to administer, length of effects, where to buy, what its comparable to(I've heard cocaine, meth, lsd, mushrooms which is a hugh variety of drugs with very different effects :?), and the name of your preffered kind. And these are legal fyi people who don't know that.