PocketMatrix

Jimmy Doom (aka Doom4CE) is alright, although it does not support custom maps, only the official wads.
gfDoom is really good, too, and it supports landscape.

Search around for them, I don't have any links. Try http://www.pocketgamer.org They have a list of every game for the PocketPC.

Only because I'm bored

Link to gfDoom:

Don't, it's absolutely horrible and abyssmal... that paradigm that if something costs more then it's better, it's not true.

In GfDoom, is there a way to "totally" mute the sound because even if i put the swith to the min in the option menu there are still some sound glitches when firing or falling.