The Danner

Have you thought about using ClickOnce for updates? Since this is a C# app, I'm assuming you're using VS, which is designed to work with ClickOnce. It doesn't need any server-side logic as far as I know; so long as you can set up an FTP connection to some public space, it should work. It's a lot harder to control where it gets installed to and a lot less flexible than a standalone installer like NSIS (what Winamp uses), but really easy to use.