I'm sorry nobody in the Red Gate community answered this. As the tools vendor, I don't feel we're really in a good position to tell you how you should go about setting up integration - everyone has their own ideas about what is good practice.
CruseControl does the scheduling of builds and gathering of reports - you could then use it to call MSBUILD or NANT to do the building. There are just so many ways to configure CruiseControl that the discussion about the merits of each would be a little long for a forum topic.
Basically, the Red Gate tools piece centers around SQL Compare and Data Compare command-lines. These can be called from CCNet or MSBUILD using an EXEC task, to do the work of checking out database scripts to a folder and building a database from that for testing, then use automated database test tools like SQL Test, and then output a migration script to upgrade a database.
There are some white papers we have done that you may want to read here:
http://www.red-gate.com/products/sql-de ... ntegration