Someone a network expert in here?

OK i have a router that connected to a DSL modem and from this router there are 1 desktop connected with an ethernet cable and 3 laptop connected using wireless card.

My question is how can i find the ip of another computer that connected through this same router? but without going to ipconfig on the target computer

Your router should have an access page. Like linksys is http://192.168.1.1 2wire is http://homeportal Once you access the router you can see the private IP’s of your computers and things like that.