'Delete' v. 'Move to trash'

[Andrew Conkling <andrewski fr st>]

Is it possible to bind the delete key to 'move to trash' or to make that  
the default action when deleting messages?  It's very convenient and  
habitual to use the Delete key to 'delete' messages, but it's also very  
convenient to have the messages not actually deleted until you really want  
them to be.

Thanks,
Andrew