SQL Server schema evolution (migrations)

There are quite a few - find a long list of alternatives here.

I've been looking into this myself, trying to avoid doing any further development on our own, internal home-grown solution (which is a mess....).

The one that I was intrigued about the most is Roundhouse

It works off SQL scripts (which is a must for me), it allows one-time scripts, everytime scripts and so forth, it keeps track of what it's done, it allows environment-specific scripts (e.g. stuff for your DEV or TEST environment that you don't want on production), it's highly configurable - looking good to me!