Everyone knows PHP can be used to create websites. But it can also be used to create desktop applications and commandline tools. And now with a class called System_Daemon, you can even create daemons using nothing but PHP. And did I mention it was easy?
This how-to was ported from: http://kevin.vanzonneveld.net/techblog/article/create_daemons_in_php/. you can leave a comment there as well.