Buy a phone with GPS and make sure the phone can run java applications. I find most phones come with a GPS that is designed to work with an internet based map system like whereis.com. The only problem with that is you will likely end up paying internet access fees.
I have a Samsung Ultra Touch phone. $40 a month on a 24month contract with Telstra. I then installed a free Java program called Trekbuddy;
http://wiki.trekbuddy.net/index.php/Main_Page
It is a freeware program which turns your GPS enabled mobile into a useful GPS. It works off stored maps, so get a phone that takes memory cards (I stuck a 2GB micro SD card in my phone). Stored maps are google because they don't need the internet, and you can customise them.
You make the maps yourself using many programs. I use one called Googleak.net. Basically you open it, select the area you want, select the map type (satellite, street, topo, hybrid), select the scale of the map and hit go. It goes and downloads all the maps from the internet and saves them in a format trekbuddy reads. Just copy them to your phone memory card and go. You can switch between map types and zoom levels as you go.
Trekbuddy also works as a track logger. You set it to record and it records your whole trip. I record mine as GPX files and set it to record a data point every 1 second. Excellent offroad as you can see where you have been, and load it into google earth when you get home. Trekbuddy also records waypoints, shows you speed, altitude, etc.
The only thing it doesn't easily do is navigation. It's maps are simply images, it doesn't know they are roads. You can't tell it an address and ask it to tell you which way to go, or when to turn left.
Wes -
www.offroadvw.net - 200HP Quad Cam V6 in a VW Baja - with climate control...
🙂
www.taylorcycles.com.au - My DH MTB racing brothers shop.
