That is for flashing a sprint phone to verizon prepaid, has nothing to do with straight talk...
and nothing to do with an Ally.
Whatever do what you want, you asked some questions I tried to help out and now its getting off topic. My opinion, you are way better off saving that $50 and selling the Ally in order to get a phone that is made for whatever carrier you take. If it is Simple talk, you can get an optimus Q which runs gingerbread, has a keyboard and is brand new for $180. Sell the ally take your 50 bucks you would throw at a stranger and you have close to 3/4 of that purchase price in hand.
My inexpensive low end android phone does everything I have asked it to do... why spend hundreds on a new flashy one?