Go to
http://www.tomtom.com/products/categ...ab4f598b9bd75c. This is the newest version of tomtom, and it will be out any day. Check out previous tomtom reviews as well as other system reviews here:
http://www.pcmag.com/search_results/...terapp=&site=3.
All the systems are good. I favor tomtom, some like pharos or copilot. The main thing is you need a gps receiver, which is about the size of a small mouse. This can be wired or bluetooth (expensive). You need a cradle to connect the receiver to the pda, and the pda to your car's power supply. Lastly you need the software. I chose to get all 3 items as a package from tomtom, other people like to mix and match.
I learned alot from this site and 2 others,
http://www.pocketgps.co.uk/ and
http://www.totalpda.co.uk/forum/.
I use it on my axim x30 mid and I love it. It is 99% accurate and the uptime is in the very high 90's percentile. It is complicated software and can freeze your pda periodically, but it has worked great thus far w/very few problems. When you read all the forums and reviews you will not be able to make your mind up b/c they're all good and they're all great to own and use.
Good luck,
steve