There are apps for that. If you want to track via GSM towers like the l33t people do, then my friend you are out of luck. Unless you can hack one of the towers that won't happen. Now on a more realistic side of things, if the phone is smart, like really smart, I mean Android smart, then you can install some apps that log and/or send GPS coords to you so you can see where the phone travels.
Yeah you pretty much limited to the GPS apps.