Using Regular Expresions to change .htm to .php in files

[sebzzz at gmail.com]

Hi,

I have a bunch of files that have changed from standard htm files to
php files but all the links inside the site are now broken because
they point to the .htm files while they are now .php files.

Does anyone have an idea about how to do a simple script that changes
each .htm in a given file to a .php

Thanks a lot in advance