Agree with above, but if Hudson doesn't work for you - it didn't for me, you can try free Mojo from OpenMake Software. Hudson was too narrowly focused. Mojo can do production scheduling as well continuous integration, so it made sense to use one tool for both of those in addition to having additional flexibility on the CI side.
Mojo actually grew out of a need for a standard tool across multiple development teams and languages, so as mentioned by chrestomanci, be careful adding unneeded complexity to your environment. As a disclaimer, I used to work for OpenMake Software, but helped make Mojo suitable for my own needs for Perl continuous integration.
Continuous integration (CI) can be complex to set up and it can mean different things to different people. The details depend heavily on your version control tool. Mojo and Hudson do have hooks out of the box for a number of VC tools, but be sure to have a clear plan. Usually CI assumes a code-compile part, but with Perl I used passing automated unit tests as an integration measure.
Mojo's GUI is very buggy, but it works solidly when configured. It easily allows you to create a job out of a perl command line, controlling arguments and environment variables. One of the best things is the real-time monitoring dashboard and the HTML wrappering and web posting of the output of all the perl cmds. It is perl/Eclipse/Java/C/C++ based, and if you use Eclipse, it can be nicely installed as a plug-in.