Converting site from .html to .php

Question

my site has now become sufficiently large for me to think it's necessary to convert the pages to php pages to help me update it in the future. The problem is: my site has a number of links to it on various websites across the web. Eg these links point to www.example.com/page1.html but the page is now going to be renamed www.example.com/page1.php

How would people get around this problem? Simply redirect the html page to the php page? Are there any alternatives? Does this have any implications for SEO?

Thanks

Answer 1

URL Rewrite: http://httpd.apache.org/docs/2.0/misc/rewriteguide.html

More directly to the point: http://roshanbh.com.np/2008/02/hide-php-url-rewriting-htaccess.html