I've got an N95 with the Symbian S60 operating system which rules out Memory Map - unfortunately.
For those of you without Windows phones, this looks good but is OS map only by the looks of things, so no nice CAA charts but very nice OS maps;
http://www.viewranger.com/index.php
PocketFMS also runs Windows o/s only.
Given that the Windows pocket PC o/s has been around for a while and the Symbian o/s is becoming widespread, I rather think it's just a case of waiting around for someone to port over the CAA maps...