The £20 CAA MM maps do come with what looks like the actual MM program.
I have never installed the program however because I have my own version on the PC already.
The way the MM PDA software is done is that you install MM on a PC and then, with the PDA connected (the usual activesync thingy) you click on the Mobile Device -> Install Pocket Navigator option, and it just does it. Very slick. I don't think MM sell a PDA version as such.
I think it will even transfer the maps that way, though activesync is painfully slow for big files; it's quicker to manually copy the .qct file(s) to the flash card.
The other prog to consider for a pocket/pc (wm2000x) device is
Oziexplorer. This is a generic moving map application which runs a wide range of maps.