I'm using an HTC Touch HD as the screen is huge and bright.
It also runs for 4 hours with the brightness up full and the GPS functional.
+ back up battery pugged in + solar charging
(Solar Charger + battery 23 quid)
Switch the phone to "aircraft mode" i.e. switch off all the transmitter functions to save battery life.
think the screen is 800 x 480 pixels so it is very high def.
only software I know of runs on WinMo.
SeeYou
WinPilot
winpilot VFR gives you pretty much everything you'll need en route.
