How do you version/track changes to SQL tables?

Question

When working in a team of developers, where everyone is making changes to local tables, and development tables, how do you keep all the changes in sync? A central log file where everyone keeps their sql changes? A wiki page to track alter table statements, individual .sql files that the devs can run to bring their local db's to the latest version? I've used some of these solutions, and I'm tyring to get a good solid solution together that works, so I'd appreciate your ideas.