Here is a link to help avoid confusion (it is not a loan):
http://www.gatherlittlebylittle.com/...-package-loan/
As I understand it (and fail to see how it can be otherwise interpreted); It is a gift, based on the size of your 2008 income, going out in 2 rounds, and this initial round will deduct how much you get in the 2nd round. The 2nd round is the tax returns for 2008, but since its meant to help the economy right now, they are sending it out early. If you get too much in this initial round you will not have to pay anything back.