+1 for everyone who's recommended the RedGate tools, with an additional recommendation and a caveat.

SqlCompare also has a decently documented API: so you can, for instance, write a console app which syncs your source controlled scripts folder with a CI integration testing database on checkin, so that when someone checks in a change to the schema from their scripts folder it's automatically deployed along with the matching application code change. This helps close the gap with developers who are forgetful about propagating changes in their local db up to a shared development DB (about half of us, I think :) ).

A caveat is that with a scripted solution or otherwise, the RedGate tools are sufficiently smooth that it's easy to forget about SQL realities underlying the abstraction. If you rename all the columns in a table, SqlCompare has no way to map the old columns to the new columns and will drop all the data in the table. It will generate warnings but I've seen people click past that. There's a general point here worth making, I think, that you can only automate DB versioning and upgrade so far - the abstractions are very leaky.