Remember this will most likely void any warranty you might have. Also there is a real possibility of bricking your phone in the process of jailbreaking and unlocking. I have hacked my Android G1 several times but never an IPhone. If you follow the steps exactly you should be successful.
Good advices above, however if you want to get a pro involved to do the job, there is a store right next to the main PN station on the Bartalome Colon. If you facing to the PN building, It's on your left. Just go few hundred yards into the little street and the shop is on your right. I forgot the name, but the owner is a pro Apple guy, servicing, repairing Macs, iPhone.