I keep getting a warning that my router is being used by another IP address - it could be my sons phone, just wondering how to find out...
what phone do you have? a good way to ensure that unwanted people do not use your wifi is to continously change your wifi password and enter the password on each allowed device yourself - thats what i do.
You should be able to look in the wireless settings on the phone and see what the ip address is. Most phones are easy to see. I would suspect an iphone since you are a mac user, if that is the case under the settings:wi-fi: then press the blue arrow and see under ip adress. :: mike