1. Google Latitude :
Google search engine has recently launched the 'Google Latitude' service which can let you track a cell phone for free. To be able to track your child's cell phone location, using this service, you will have to install this program on his or her phone and make sure that he has added you as a friend on Google Latitude log in. Once you are connected with him, you can easily track his whereabouts by installing Google Latitude on your phone too. You can easily track the location of friends and family on Google maps, using this facility. Most importantly, this service does not require your phone to be GPS enabled.
2. Buddyway :
Another online service which provides you with a similar facility to track cell phone location is Buddyway. Install the Buddyway application on the cell phone of any person you want to keep a tab on, without them knowing and then follow their movement on a web interface by logging in. The service record entire route of travel and the path can be seen in Google Earth 3D. Visit the Buddyway website to know more about tracking a cell phone location.
By bugging phones with any of Google Latitude, Buddyway or other such applications, you can track cell phone location and keep track of the movements of your family members, for safety purpose. There are many more web services, that let you track your children's movements online. Most of these are paid applications, but the two that I mentioned above are absolutely free. However, you need to be sly enough to install them on your child's phone to be able to track him or her without letting them know.