I am looking for a GPS Unit – but I dont have a clue about them. Basically all I want to be able to do is upload GPX routes from the internet onto it and then use it to guide me along said route.

Can anyone reccomed a simple, easy to use, relatively cheap unit that will have this functionality?

As a side note – is it possible to track a GPS Device via a laptop/mobile phone? Say you were out for a long xc ride (as a group) would it be possible for someone to track where the GPS unit was that the group had in their possession?

This might all be very simple, it might all be very complex – but I dont have a clue either way. I have looked at the Garmin 800 but its too expensive – do some use maps (in a similar way to nin-car satnavs) and others use a small arrow or something?

I dont mean to sound dumb – any help greatly appreciated.

Oh, and I dont want to rely on mobile phone – I have tried this via 3G and by downloading the maps – it always seems flaky and boils my piss when it doesn’t work

Garmin 810 + mobile will do all this, but its not a cheap option.
If you can live without the real time tracking, etrex 20 + talky toaster maps would work well.

There are two basic types, map based ones, Satmap and the more expensive Garmins, or the more basic breadcrumb style ones. I have a Garmin Edge 305 which has a breadcrumb trail. Basically you can plot or download a route or course on a GPS site, then follow it on the ground. The breadcrumb trail idea is simple. More obvious on road, but off road it bleeps to show you when you stray from it, and points you back on course. Off road I carry a 1:25000 os map in my pack. The two complement each other very well.

As for a tracking function, I expect a smartphone would do that better.