launchd editor:

"Launchd Editor is a GUI tool that lets you set up your own lauchd items without having to use the scary Terminal (and if you aren't a least a little fearful of the Terminal, you should be. You can really screw up your Mac in the Terminal, though in the right hands and with the proper respect you can also accomplish great things). For 5 bucks, which is suggested, you too can use Launchd Editor like a Unix jockey. Before you know it you will have everything on your Mac running on a tight schedule."

(Via The Unofficial Apple Weblog (TUAW).)