Multiple Permalink Structures for WordPress Move ?

Hi,

I’d like to move my wordpress install from mydomain.com/wordpress to mydomain.com , I’ve been reading the “move” documentation on codex, but can’t see about how to keep my URLs working.

The Default re-write rule (currently)
RewriteRule . /wordpress/index.php [L]
but will be
RewriteRule . /index.php [L]
Means that wordpress will see the old URLs and return 404’s, is there a way (plugin maybe?) to keep serving the old url ? i.e. both http://mydomain.com/wordpress/permalink-structure and http://mydomain.com/permalink-structure work ?

Thanks in advance,
Nick