This interesting project is specially designed for motorcycle trips which let to track its location with a twitter messages. Module is equipped with PIC18F25K20 microcontroller alongside GPS and GPRS module GM862. Device reads GPS location and sends twitter message every 60 seconds along Google Maps link. This way those who stayed at home can easily track your location with no worries.
So instead using expensive tracking devices consider using this one – the only cost is related to amount of SMS sent.