You have two choices: LT1 Edit and Tunercat, marketed by Jet. Of the two, I prefer Tunercat. It is currently available in two flavors, one with two licenses and one with four. Unless you are going to tune multiple cars, the first will do fine. AFA more licenses, it is Jet's way to charge more money, the s/w is unchanged, and you save no money upfront. I think that Jegs still has some with two.
You will also need scanning software to do data logging. I use Autotap, which is old, clunky, and rife with bugs. But it does the basics, and you can sometimes find used copies for sale online.