I just got a EEE pad transformer. Like any hardware I own I\'d like to have a C compiler on it. I know I can cross compile, but I\'d like to do development ON the device i
Since you asked about this in June, 2011, (or maybe starting right around that same time) there's something that does EXACTLY what you want called "Terminal-IDE." This is a much better answer than the one you checked off as correct because it doesn't rely upon cross-compilation as the checked answer does.
Terminal-IDE is an Integrated Development Environment that runs ON your Android device (just as you asked about), and has both a C compiler and Java (of course).
There's a Terminal-IDE web site with a more in-depth description and links to other resources.
NOTE: Since I wrote this reply, the author of Terminal-IDE has stopped supporting it. Please don't down-vote me because of that!
The process of building gcc (et al.) to run on your target should be similar to building a cross-compiler, excepting that you will:
--host
option to specify your ARM platform when running configure
for all of the parts of your toolchain.