GREG - MIG is pretty easy, there's LOTS of information in books and on the web. I wouldn't start trying to do serious structural welding right off, and even having welded with NO formal instruction since Dad let me burn rod as a small boy, I try to stay far far away from out-of-position welds of any sort at any cost.
Far as which welder to start with, I'd suggest Terry's choice or a comparable blue one, Miller. They're both made by the same company, ILL Tool Works, ITW. I would suggest if your serious about welding, get something that runs off 220V, the 110V models are nice to start but as your fab skills improve you soon find yourself limited by your ability to properly weld thicker material. I set myself up as capable to properly cut & weld 3/8" material but have had no problems exceeding that like with the 2" x 2" steel bar I welded to some 1/2" thk steel plate that is the catch for the trip bucket on my loader years ago.