I learned G, C, & D chords, and practiced changing between them in different orders. Once you get to where you can go from C to D, C to G, and G to D with ease, start looking up some simple songs with only G, C, and D. Then start adding other common chords like E, A, E minor, A minor, and F and start playing songs with those chords also.
Your fingers will stop hurting after just a couple weeks as callouses build up. You'll soon learn that your left hand (assuming you are right handed) is the easy one to learn...rythms are the big challenge.
Keep practicing...it'll come quickly. I was the only one who brought a guitar to the tourney, but I sat down with a cajun band on Saturday night there and had a great time playing a type of music I hadn't had opportunity to play much.
