While setting some svn properties at work, we wondered about the correct MIME type for .php files.

He found several in the official IANA list including "text/php", "application/php" and "application/x-http-php" - all valid but none of them considered a standard. He talks about the ones supported by linux distributions (like Debian/Ubuntu) and some reasoning that might make "application/php" the best choice of the list. He points out some downsides to the choice, though, including the fact that something starting with "application/" should considered "machine readable" only despite PHP just being text.