Continuous Integration and CCNet

Continuous Integration is a software development practice where members of a team integrate their work frequently, usually each person integrates at least daily - leading to multiple integrations per day. Each integration is verified by an automated build (including test) to detect integration errors as quickly as possible. Many teams find that this approach leads to significantly reduced integration problems and allows a team to develop cohesive software more rapidly.

CruiseControl.NET (CCNet) consists of a suite of applications, but at its core is the CruiseControl.NET Server which is an automated integration server.
The Server automates the integration process by monitoring the team's source control repository directly. Every time a developer commits a new set of modifications, the server will automatically launch an integration build to validate the changes. When the build is complete, the server notifies the developer whether the changes that they committed integrated successfully or not.

Found good article to get started with CruiseControl.NET:
CruiseControl.NET from Scratch