On its website, Redgate has posted an overview on Database Lifecycle Management. It's a real problem, and one that has note been completely solved. Application code can be ripped out, and replaced wholesale. Not so with the database. While there are bits of what we might call code, the database is really the data, with a small bit of code. But once setup, it's live. There are no cut and paste approaches. Changes have to be well understood, and implemented with caution. Redgate's whitepaper can be found here: Solving the database deployment problem with DLM.
They also have a free DLM tool, called DLM Dashboard. while it is part of the full SQL Toolbelt, you can download just the DLM Dashboard for free. Redgate is a great operation, putting a lot of effort into supporting SQL Server, including its sponsorship of http://www.sqlservercentral.com/.
You can find the DLM Dashboard here: http://www.red-gate.com/products/dlm/dlm-dashboard/.