I recomend the Free Homemade Method:
There is also a free method which is what alot of people use as well its simple, doesnt cost any cash and takes a couple seconds and a screwdriver (torx 7). You cant beat free!
You dont have to go to the store, No waiting for your order you can transfer your saves right now!
You wont void your 360 at all! even though technically using Xsata and all those other waste of money gimmicks voids your warranty as well, You would just be voiding your save device (HDD) For a 99 dollar hard drive spending 50 bucks is half of that! (Too Much) XPlorer 360 is the way to go!