I'm currently in the process of finishing up my garage. The only wall that is insulated and has drywall on it is the wall that my attached garage shares with my kitchen.

I've already run all the additional electrical outlets that I want and getting ready to start insulation.

I've decided that I'm going to go with either plywood or OSB instead of drywall for the remainder of the garage.

However, talking to a friend of mine said I might want to check the building code to make sure that I don't do it and hurt myself when/if we ever sell.

Who could I call or where online can I find out about it?

Google Wake County building permits.  You might want to tread lightly.  I believe you were supposed to get a permit or permits before doing the work, so divulging your new electrical work might get you in hot water, especially if it is not up to code.

I also believe you can't use plywood or OSB inside the attached garage as it can be a fire hazard.  Gypsum or drywall is a fire retardant and that might be the reason I don't recall ever having seen a garage finished in plywood.