Jenkins is a Java-based CI server package.  It is commonly used for Java projects but is suited for .NET projects because Jenkins can work with many common .NET version control systems, can run MSBuild scripts, and has a very active plug-in development community.  In general, much of what any CI server does is not .NET specific.  The primary component of Jenkins is the server, which runs within a Java servlet container, such as Apache Tomcat.

Jenkins is easy to install and use; the fact that it is Java-based should not represent an impediment to .NET development shops.  Jenkins provides an impressive browser-hosted project management dashboard.

For those familiar with using Jenkins for Java development, the advantage is in using a familiar technology.

Some of the reasons to evaluate and choose Jenkins include: