It seems quite a lot of people would like to run Cassini as a service on their systems. Because of that question, I created a sample that allows you to do so. It can be downloaded from
http://www.bartdesmet.net/download/Cassini.zip. Included is the source as well as a setup project with an MSI installation of the service.
In fact, this is just a part of a project I've done with Cassini to create a secure download center for software on the internet. I did not review this solution completely (made it in an hour or so), so there can still be bugs in the code. If you've further suggestions to improve this solution, please let me/us know, I'll make the mods then and put the refreshed files on-line.
Cheers!