Emacs keys
CTRL-X S (hold down control for both letters)
Save your work
CTRL-X C
Exit emacs
CTRL-G
Abort current command (if you accidentally typed something wrong)
More:
(Quick intro)
http://www.cs.washington.edu/education/courses/cse326/00wi/unix/emacs
.html
(official documentation)
http://www.lns.cornell.edu/public/COMP/info/emacs/emacs_toc.html