php as php3 perhaps with htaccess

Hello, I have a website and all my files are *.php3 I would like to change the extensions of all files to *.php My problem is for the search engine and links to my site. Because the site is well referenced in the search engine with files liek *.php3 So if I rename all files in .php, the links in the search engine will be broken So I would like to know if there is a way perhaps with a .htaccess file to say that the file .php3 must be redirect to the same file but in *.php So when I try to access this page : http://www.my-site.com/page.php3?param=value I will access this page : http://www.my-site.com/page.php?param=value Thanks a lot