I got it from shiftmaster. Here's their web address:
http://www.eec-tuner.com. I use it with a laptop, but it comes with a power adapter so you can hook it up in your house and download your programs. Its pretty easy to use, you just type in your settings (this is the hardest part), hit download with the key forward, then turn the key off then on again for about 2 seconds, and then your program is uploaded. This thing is amazing!