Possible Duplicate:
Redirect *.htm to *.php
htaccess rewrite if redirected file exists
I set up a website a while ago and I had all the extensions as .html. I've learned a bit more about web development and would like to have everything as .php. The problem is that some of the pages have been bookmarked so I can't just change all the links and remove the .html files. I understand I could just add redirects on each page, but that would mean having two of each page on my site.
I'm wondering if there is a way using .htaccess to redirect any *.html to *.php if *.php exists.