You can now track the location of your phone based on GPS and cell phone tower. This will be very useful in case your phone gets lost. I guess you can also install it into your kids phones and check their location. I don't know it they will like it or not but will definitely help an anxious parent.
But you will need a Nokia S60 V3 or V5 phone. Works also on certain Samsung and Sony phones. Here's the detailed list
Here's what need to do:
1. Open ovistore in your phone
2. Search for a software named "Periodic"
3. Download and install it
(You can also download it directly from the developers website. Use the Ovisuite PC application to install it into your phone)
After the application is installed,
Go to "options" and register your phone.
After registering go to "options" and click "complete registration"
You can use the software to update your location to your online account at periodic.
Here's my trail :)
You can go to settings and select the update frequency. Setting it to 6hours will be ideal for minimum battery usage. You can also set a "buddy number". This number will receive an sms of your current location if the SIM card is changed. Very useful if your phone gets stolen.
Update 28.07.10: The screenshot in this post shows my online account map showing my trip to Athirappilly Falls. The software is working nicely.