more information is also at Emacs and EmacsWikiMode on PDAs
Latest (almost 188.8.131.52 - 2007-03-12) compiles natively too, check out the other postings in the forum for useful Zaurus/Emacs tips
AN older version (Emacs 21.4) compiles natively on the Zaurus clamshell and SL6000 models in pdaxrom.
default fonts don’t work. start emacs with -fn 7x13 sometimes you need to set -q
One more port of Emacs 21.2.1 for Sharp Zaurus (Qtopia) you can find here:
emacs 21.4 (console) available here:
There is also a port of XEmacs there but I never tried it.