I'll give the OP a little more information on the subject.
Most of us on here go with either an SCT Chip, an Xcal2 or an Xcal3. These are the most readily available and cost effective ways to tune our cars. You can go with Jet or Diablo, but i've seen both of them in action as well as SCT's Advantage software and was *personally* more impressed with the SCT setup.
If you want to do the tuning yourself, your best route would be and Xcal2, Xcal3 as well as the PRP (Pro Racer Package). However, if you do not know what you are doing, I do not recommend this route. It isn't something someone without a decent background in engine management can pick up, throw some numbers at and expect a good outcome.
SCT (Superchip) Chip - Plugs into what is called the J3 port on your computer. On *some* vehicles, this port is disable from the factory, which means you will have to pull the PCM, open it up and do some soldering. You can plug in the chip and see if it works, but if the speedo gets pegged and the car won't start, you will have to "open" up this port. One other warning with this one, make sure once the tuning is complete you should use electrical tape or something equivalent to hold the chip in. I had mine knocked out of my 00 SVT and it fried both the PCM and the Superchip. Just a word of advice, learn from my mistakes...
Xcal2/Xcal3 - Both plug into the OBD-II port and overwrite the factory tune with your own tune. They then save the stock tune so you can return the vehicle to stock if need be. While on this, if you pick up a used Xcal2/Xcal3 make sure the previous owner has returned their vehicle to stock. If they have not, you will have to take the Xcal to an authorized SCT dealer, have them send the Xcal to SCT to be unlocked and pay a fee (IIRC ~$150). Not fun when you just paid $175+ for a used Xcal... For the average user won't make too much difference which one you go with (Xcal2 or Xcal3). The main advantages of the Xcal3 are the bigger screen and faster upload/download times for tunes. This can be nice if you change the program often.
Any questions?
EDIT: When you do it, make sure whoever does it knows what they are doing. Joey at Nautilus does good work and there are a few others that have done good work. My tuner has done quite a few SVTC's and my car was an absolute BLAST to drive once it was tuned. Think big torque gains and a top end that seemingly never ends...
