I'll second the "Orvis Fly Fishing Guide". It's a great book for a beginer.
If you're from central PA you've got some wonderful fishing around you too. I'm from South Western PA and my fishing partner and I make quite a few trips out your way to fish every year. There's Penn's Creek, Spring Creek, Spuce Creek (although most of Spruce is private water, there's the George Harvey section that's public) and our favorite the Little J.
If you're in the State College area, Fly Fisherman's Paradise is a great shop that would be worth your time to stop by. If you're in the Spruce Creek area there's Spruce Creek Outfitters, which is a great shop too and then there's one of my favorite fly shops, Spruce Creek Fly Company. Those guys always offer great advice.
-Darryl
My one wish is that when I die my wife doesn't sell my fishing stuff for what I told her I paid for it...