Yea, I'm pretty sure it's usually for two years. Also, if you apply directly for a M.S., it usually isn't funded, however, some people will apply for a Ph.D., get the Ph.D. funding, and then just quit once they have their master's. From what I understand though, having done this looks really bad when you reapply. In fact, I heard somewhere that if you have a master's degree at all, many departments will just assume that you dropped out of a Ph.D. program... I kinda doubt that this is true though... can anybody confirm?