Picking up someone wireless connection

[YupChaGi]

I just setup a wireless network at home now that I have DSL. Last night my son came to me to tell me the signal strength on his computer was low. So when I checked it out I noticed he was not connected to our SSID. So when I checked the available connections there where two additional connections, one Linksys and one Netgear. So to check things out I turned off my wireless router and was able to connect to the Internet using ether of these connections. So now I know I am picking up someone else’s signals. Here is my question, is there a way for me to look at there system to try to find out who this is so I can let them know they need to close there network?

Dave

[ins_]

well, it must be someone close to you, if you're friendly with your neighbors ask them.

if you live in an apartment building, it might not be so simple

[qball15j]

Your taking the right approach and its definitely the right thing to do.
I would recommend locking down your wireless network either with WEP, WPA or MAC Filtering. Since you do have other networks in range they could be leeching off you and not even knowing it.