This is probably old news to most. But since I just got my first iPhone, I just wanted to make people aware that thanks to the latest "Don't Panic" skin, m48 is vastly more usable and the best 48 emulator I've seen on the iPhone. It looks absolutely stunning on the iPhone 4. The keyboard changes when shift and alpha keys are pressed, and you can use swipes on the LCD instead of the cursor keys. Very nicely done. Before "Don't Panic" there were a lot of skins, but many were hard to use/read. So if you haven't tried m48 lately, give it another shot. You'll be pleasantly surprised.
When I got my iPhone, I tried all the free HP emulators, and this one is by far the nicest. (I use m48 which is the free version. m48+ is the fully featured version).
Kudos to Marcus and ultimately Christoph and Sebastian who made this 48 emulator possible.
Edited: 12 May 2011, 11:58 a.m.