The Emacs Keybinding Guide by JariAalto will tell you more about keybinding than you ever wanted to know.
Very easy way:
I think it tells you more than you wanted to know in terms of mis-information and dubious opinion. Please see the EmacsLisp manual. If that doesn’t help, make a bug report against it. If you want examples of doing things portably between Emacs and XEmacs, have a look at Gnus, for instance. – Dave Love