custom keyboard layout? howto redefine keys?

[nic . d . m . 1]

Is there a way to customize the keyboard layout within emacs? For
example if I want "the key on my keyboard labeled 'a'  behave like
that labeled 'b' I think the code for my .emacs file should be
something like this:

(global-set-key ["Key labeled 'a' on my keyboard"]  'ucs-insert 0062)

I am new to emacs and don't know what the correct syntax for "Key
labeled 'a' on my keyboard' could be.

So I tried to make f5 instead behave like b:

(global-set-key [f5]  'ucs-insert 0062)

Then I get an error message: "Wrong type argument: commandp, (ucs-
insert 62)" if I restart emacs and press f5.

(For example (global-set-key [f1]  'ucs-insert) works, but then it
asks which UTF-8 character I want to insert, that's not what I want)

Any ideas?

thanks
nic