menschmaschine said:
Some of the more commonly used chords are A, Am, B, Bm, C, D, E, Em, F, G.
One way to do it, would be to pick a relatively easy song you like and learn those chords. My first one was "Free Falling" and when I could play that song, I thought I was the greatest.
I've been playing various musical instruments since grade school. I never REALLY mastered any of them, but I've got a solid enough musical background to grab nearly any instrument and at least become an average hack at it within a few weeks. For the last few years I've been focusing on the guitar. It's been very rewarding, but I haven't committed enough time to really get good at it.
Regarding the open chords, mensch is exactly right...except that I would try to learn them in the following order:
G, C, D, Am, Em, E, A, F (not barred), F (barred), Bm, B
When learning
Free Falling, learn to play it in the key of D using the simple chords:
D, Dsus4, Dsus2
It will sound TERRIBLE if you play along with the CD since you're learning it in a slightly higher key, but it's quite simple, and it's a great strumming exercise. Since playing it this way is pretty easy, it makes for a good first song to learn to play and sing at the same time.
When you're ready to step up the difficulty, learn to play it in the key of E (tab is available on the Internet). IIRC, the CD version is in Eb, played on a guitar that's detuned a half step.