redirecting directory to static .html

[SEO2Go]

I recently updated a directory site of mine and the newer version gave the option to change the listings from:

http://www.example.com/redwidget/ to http://www.example.com/redwidget.html

I'd eally like to stick with the newer version, but my established links ending in / in search engines now produce 404 errors when clicked.

I think I need to edit the .htaccess file, but I'm not sure how to make the first example redirect to the second example.

Any suggestions would be greatly appreciated. Thanks.

[edited by: phranque at 7:55 am (utc) on Aug. 24, 2008]
[edit reason] exemplified urls [/edit]

[phranque]

why would you want to change the established urls?