Need Help Setting Up a 301 Redirect

Hi,
I've updated my site and now I need all people who go to a URL like this:

http://dodesign.us/designs/bold-orange.php (OLD)

to be redirected here:

http://dodesign.us/designs/bold-orange/


Basically, If the URL has the /designs/ part, then I need the last .php removed and a / added instead.

Please help. Rep for any who help.

 

This should do the job. Copy it to notepad to remove any board formatting: