If you have access to an iPhone 4 (not own one, just access) you can get Apple's FindMyiPhone for free. You do NOT need to be jailbroken. The program is ok but lacks features. You can only view the location real time (so no automatic logs), send a pop up, sound an alarm or wipe it.
If you are jailbroken there are several good apps. Findmyi, iLocali, and Cylay. They offer tons of features (makes them more useful for tracking a stolen phone) but cost about $20 per year. Most offer trials so just try them out and choose the best. They should be in cydia, but google is your friend.
Do not use any appstore apps as they do not automatically restart tracking if the thief closes them, and they are very easy to delete.