Right folks, I've been asked to re-post this information by another member whose post got 'disappeared' somehow!
This Co. http://www.fleetonline.net/fol/uk/en/ has a service whereby they will locate the position of a mobile 'phone (within a few kms down to 50m, on a map on your PC). You need to register the mobile (cheap one-off fee) and then pay a fee each time you do a location request.
I haven't delved too deeply into it myself, but with a mobile phone, on charge, in the 'van and hidden somewhere, it does provide a very cheap form of 'tracker' device. Of course it doesn't 'phone you to say it's moved position, or that the 'van's been broken into etc, like some of the other SMS/GPS security systems. But then they cost £300 and up and Phantom & Tracker require an annual fee as well.
Presently this fleetonline service seems confined to the UK at present.

