Like the guys have mentioned, both Diablo and Bullydog have tuners available for your truck. The Diablo units are custom tunable and offer much more control. The Bullydog unit is more designed for the guys with the basic intake and exhaust upgrades. While both tuners will show considerable gains over stock, the ability to have a custom tune written with Diablo is what sets it apart from the rest.
As for the tunes and what octane fuel to run, you want to make sure that you always run the recommended octane or higher than what the tune calls for.
A catch can is also an important mod when it comes to adding a tuner. Without a catch can, I would always run 1 fuel grade higher than what the tune calls for. If you have a catch can, then you are OK running the same grade of fuel that the tune asks for. Running a lower octane fuel than the tune needs will cause spark knock...when the computer detects knock, it will pull timing and cause you to lose power.