I'm running Cygwin on Windows XP. I want XWin to start as a Windows service. How can I configure this?
You don't. Services are not supposed to have access to the1 user's desktop – this was actually removed in Vista – and without it, XWin is sort of useless.
Just put XWin in your "Startup" folder.
(1 I said "the", but Windows XP has "Fast User Switching" on by default. There may be multiple users logged in at the same time. Which session would XWin run on?)
[Now, I'm going to hate myself for this, but] you can run arbitrary programs as Windows services by using a Microsoft tool