If you're not the "do it yourself" type, you can have someone else tune it, or you can buy a Predator programmer from any of the great sponsors here. You'll see some gains from both, but the tuners almost always get better hp/tq gains because they take the time to tailor the tune to YOUR individual car. Both are good though.
The days of the chips you put in your car are pretty much over due to the complexity and multiple-computer set-up of most newer cars. The old chips basically intercepted the data and changed it to give more performance before feeding it back into the computer. Of course back then, the computer wasn't responsible for as much as they are today.