I'd go with an 8.5-9' 5wt. That's a very versatile rod. Also, I'd get a combo (rod, reel and line already put together for you.) That way, you don't have to "mix and match" and figure it out on your own. Here is one good combo:
Amazon.com: Scientific Anglers Species Specific Fly Fishing Outfit Combo: Sports & Outdoors
It's rigged and ready to fish. It even comes with a DVD. I'd get the Panfish or the Trout model. (The only difference is the DVD that comes with it.)
Other good combos are:
Bass Pro Hobbs Creek
Cabelas Three Forks
Redington Crosswater
A TFO combo will cost you a little more, but they are excellent rods and they come with a lifetime warranty. I have two TFO rods and would recommend them to anybody.
If you like to read, here is an excellent book:
Amazon.com: L.L. Bean Fly-Fishing Handbook, 2nd (L. L. Bean) (9781592282937): Dave Whitlock: Books
Also, check the newsstand. Fly Fisherman magazine has its annual "intro to fly fishing" issue out right now. It has a lot of good tips in it.