Just to interject, there's no such language as "sign language". That's like saying "I want to learn Spoken Language". Each sign language is a distinct entity - you want to learn ASL, or CSL, or BSL, or whatever.

deaf isn't a bad idea, they should be able to point you in the direction of some good online resources - and most communities have classes in ASL (at least, in the US they do!) that you could take.