Hmm, be careful re the 3 month thing. I have known agencies to have clauses in their contract demanding 90 days notice! And they will usually hold back US$500 or so every month as a "completion bonus". So if you leave before the notice or break any of the multitude of clauses they will keep this money! It can add up over a long contrat so beware.
(And they don't even put this money into an interest bearing account for you!)