If you are a geek, you might be interested in how we managed to track Janey. In summary we put this together with GPS tracking/collection with a cell phone for under $11/month and Google Maps API.
We chose to do this using a cell phone to keep it simple and having a phone on hand at all times is always useful. Trying to keep a PC powered in harsh environments (like an old rover) isn't a good idea.
This is surprisingly harder that you'd think because most cell phones and cell phone providers don't let you get access to the GPS data! I poked around for a bit and tried using several phones I had access to on the verizon network (Treo 650 running Palm OS, Motorola Q running Windows Mobile 5, and Motorola Razr running Symbian) but the bottom line was you either couldn't get access to the GPS data, even if you could write your own code. I tried Navizon on my Q and this could have been a workable solution for approximate location, but the phones are just too expensive (and I wasn't giving up mine ;) ).
One of Mike's co-workers pointed us to this thread on mp3car.com which explained you can sign up for Boost Mobile prepaid and after a one time cost of a relatively cheap phone, you can get unlimited data access for $0.35/day and let you access both the GPS on the phone directly, but also AGPS from the provider (nextel). I checked it out and since it runs java I knew it would work and purchased a Motorola i450 for about $80 and it included $10 worth of boost payments.
I was going to write my own midlet, but found the excellent Mologogo app supported posting the GPS coordinates to an alternate URL (instead of just to their site) so there was no need.
More to come on this when I have time..
Using the Google API is surprisingly easy. Most of the work was in developing an administration interface to allow Mike to define trip legs, markers and otherwise document the trip. If you are so inclined, a large part of what it takes is available by viewing the source. The rest is just a mysql database storing the data and some php scripts to generate XML out of it.
More to come on this when I have time..