I have found that Navigator is a collection of Discoverer map regions. Same software, just bundled together and sold as Navigator.
The software is for both Desktop PC and Pocket PC (bundled together in same box)
The software includes live GPS location and active map tracking/scrolling (even shows a trail of where you have been!)
ONLY 2 NEGATIVES:
No 3D map view for Pocket PC.
Region map data is large, better fork out on some CF memory if you want the whole collection on your PDA. Unless you live in Landsend or John O'Groats, I can't imagine you would want to load all the maps on together.
regs
frostytwospoons
(enjoying a life online...

)