I used to compare weddings to drug dealing. If you screw up, your career is screwed, but the money is so damn good sometimes it's hard to keep from doing it.
That said, I did a few weddings for friends or for other photographers who didn't want to do it back in the mid 2000's. These were small affairs. It typically went like this:
Bride: Can you shoot my wedding? I don't have much money
Me: Sure, I'll do it for $500
Bride: Great! I want this, this, this, this and this shot. Oh, we're only getting married because I'm pregnant. Hay can you come over here and get a pic of me and my girls smoking up before the ceremony?
Me: Uh.....wow
Bride: I'll pay you soon I promise
Me: I'm not giving you the pics until I get paid in full. $500
Bride-6mo Later: Here you go.
Me: *facepalm*
If you're just looking for some experience in doing it, go to Photo.net or some place. They are always looking for beginning photographers to shoot. Just make sure you fill them in on expectations and don't let them book without confirming they know what they are getting. I think local bridal forums or registries have people looking for the same.