Something on my computer is binding to port 80. Short of manually turning on and off every process on my computer, how do I find out what process is binding to what port? (Windows XP, SP1)

Update: Thanks for your responses (mainly via MSN). It turns out it was Skype, the pesky thing, but at least it wasn't some sinister spyware. Thanks to Steve (he's a fan of uber-minimalist web design) for the pointer to the thoroughly useful TCPview, which was exactly the tool for the job. SysInternals seem to do a lot of other useful stuff, too.

I love my blog. I could've gone looking for that answer, or just sat here until somebody popped along and answered it for me.