How to remap ~ key?

[Rory Campbell-Lange <rory@campbell-lange.net>]

I am using a 1.5GHz 15 inch PowerBook. 

The ~ key on my keyboard has moved down to where apple puts it! I'd like
to swap input on the +/- key under escape to ~/` and vice versa -- or
even to use both as ~/`. The keycodes for the target key is
    '0x56 0xd6'
and the code for the existing ~/` key is 
    0x29 0xa9

Thanks for any advice;
Rory

-- 
Rory Campbell-Lange 
<rory@campbell-lange.net>
<www.campbell-lange.net>