I just got acquainted with the Database Project in VS.Net. Very cool. This sample chapter gives a very nice intro on the Hows and Whys of it(PDF). I'll be adding this to my current project shortly.
Some of the main features - you can put your SQL scripts in the database easily and reconstruct the whole database (inc. data!) from within the project. Lots of other abilities, but the main thing is that it allows you to generate the scripts automatically, and even create change scripts automatically when you change the schema. Very nice.