Solving "Address already in use"

[Joe Emenaker <joe@emenaker.com>]

Here's a wierd one.

Our SpamAssassin daemon crashed and, when I tried to restart it, I got:

 Could not create INET socket: Address already in use IO::Socket::INET: 
Address already in use

... and I can't find any running spamd, so it looks like it's a stuck 
socket.

I haven't seen one of these for a long time but, in the past, we'd have 
to reboot the machine in order to fix it.

Is there a better way, these days? Can I forcibly "un-use" the port? If 
not, can I, at the least, find out what process ID's the kernel thinks 
have it open?

- Joe