Its quite amazing google latitude alows you to track down the location of your mobile or your friends.
It works kind of like a GPS but it dosent require a GPS. It will send a msg with a link to download and install an application on the mobile phone.
Google Latitude is a feature of Google Maps for mobile on these phones:
* Android-powered devices, such as the T-Mobile G1
* iPhone and iPod touch devices (coming soon)
* most color BlackBerry devices
* most Windows Mobile 5.0+ devices
* most Symbian S60 devices (Nokia smartphones)
* many Java-enabled (J2ME) mobile phones, such as Sony Ericsson devices (coming soon)
Go ahead and try it out: