I was going to post about this for some time now but never got around it.
This is a post for DIY tracking and will not count for anything or give any discounts for insurance companies but it is cost effective way if you just want to find your car when it's stolen or if you want to see what your kids, other half or garage guys are up to when they get their hands on your car.
I have been toying with the idea for a while. I ended up buying second hand HTC Wildfire phone on the e-bay for £40, and cigarette lighter USB charger for £0.99. I chose Wildfire as it's cheap and I have HTC Desire so familiar with HTC phones and Android operating system but most of Android phones should work and similar options are available on iPhone as well. For network connection I chose GiffGaff top up card, topped it up with £10 and got £15 credit as it was on some kind of promotion. I have used it for 5-6 months now and it has been active probably for half of the time set to upload information every minute and it has just over £5 still left on it. As it is phone it has it's own battery and will work for extended period of time without external power for example if battery gets disconnected.
I tried lot of software before permanently installing it in the car. I ended up using Real Time GPS Tracker(
http://www.greenalp.com/RealTimeTracker/) software which is free and offer range of options and settings. As it is based on Google location services it use GPS, wireless and cell technology to determine location. GPS gives accuracy 2-24m depending of signal quality, if GPS signal is not available it searches for for available WiFi that Google has mapped with their Streetview cars and gives 20-150m accuracy, if that's not available as well then it relies on cell location data which range from 100m to several miles depending on location. It has a range of options like setting location update interval, upload interval and other options. Combining with other software you can also set range of movement before updating location. If You are BT customer you can enter your login information on the phone to connect to top WiFi hotspots o you save on data transfers.
The free software offers you to view real time location on another Android phone or webpage. Webpage also shows recent track record. For EUR2.4 a month or EUR12 for a year you get track loading feature which saves all the location data while the feature is active and tracks can be loaded on the map or exported at any time.
It also offers activation/deactivating from webpage or sending SMS message from another phone.
I have included couple of pictures to show it in action
