Ip address conflict

I have two computers with an ip address conflict. I know how to resolve the issue, but what i want to know is. How can i find the other machine using the address? I do not want it using it because it is in a certain range and should never have been assigned to anything. It could be a win98 or 2000 machine. Maybe even a printer, but I doubt it. Can i find out who has this address, maybe by username or machine name? I have not gotten a response from anybody getting a duplicate ip message,which i think i should have.

thanks