Hi
I am an electronic engineer with quite an expertise in tracking(Hardware,firmware and software) design. I have prior GPS development experience on Smartphone (Android), Web (php, Java, Javascript [for user interface + google maps]) and Hardware(Telit's GE864-GPS).
Hopefully, I will be able to complete your task within 3 days. Kindly note that we will need a web server (to aggregate location data from all users).
The developed android app will be able to localize via GPS as well as GSM (crude yet fast locations + available on locations (like indoor) where GPS doesn't works). Further, developed app/monitoring system will be accessible over all internet enabled devices (means not limited to android) such as smartphones, PCs, PDAs, IPADs etc.
Thanking in Anticipation
Rana Muhammad Bilal