Alternative "defun"

I am trying to write a macro which works the same as defun - with name as "def"... Can anybody help? I think you can't write a function for this since you need to evaluate the name of the function, eg,

(defmacro def (name parameters body) ?)

And the other problem is that there need to be multiple optional arguments and the body of the macro.
TIA

Usually defun is defined something like this:

(defmacro def (name lambda-list &body body)
  (setf (symbol-function ',name)
        #'(lambda ,lambda-list ,@body)))

Shameless plug: http://common-lisp.net/project/definer/

cheers