for your project, you will need a GPS module and a GSM OR GPRS module. basically for GPS, it is purely a receiver that tells you your actual position, speed, altitute etc...and inorder to track the object, you will need these information to be transmitted over air to a "command centre".For transmission, a simple GSM/GPRS module will do the trick, depending on how you would want to use this set of information, you could also program a microcontroller to control the I/O of these information.
A write-up is available on the Maxim website:
**broken link removed**
Hi,
U need two wireless modems ( I use Wavecom GSM). Interface one of the Modems to GPS thru' a UC and then at the receiver end you may directly connect it to the PC/other RS232 host.
B R M