the item in Mr. X post lets you hookup a paintball cylinder to a standard CO2 regulator.
If you don't have a CO2 regulator, they have one for paintball tanks.
I will add that I hope you're only doing this to be able to take a keg to remote locations. A 9oz paintball tank will carb and dispense about 1-1.5 cornies. its hardly economical...but is convenient for taking kegs to parties/camping trips/on safari.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10