I had a post written asking how to get php working, but I answered it myself before I submitted, so rather than just abort the message, I'm just going to post the answer. It seems incredibly obvious now, but somehow I didn't notice earlier.

1. Rename /etc/apache/php.ini
2. Replace it with /etc/apache/php.ini-recommended
3. Edit /etc/apache/httpd.conf and uncomment the line "include /etc/apache/mod_php.conf"
4. (optional) Still in httpd.conf, search for the line with "index.html" and add "index.php" right next to it on the same line
5. Save and exit
6. /etc/rc.d/rc.httpd restart
7. Put a .php file in /var/www/htdocs

I'm pretty sure that's all I had to do.. it was step 2 that got me, because I didn't notice the collection of ini files.

MySQL isn't working either.. hopefully there's something similar for that app.

To get mysql working do this:
# su mysql
# mysql_install_db
# exit
# chmod 744 /etc/rc.d/rc.mysqld
# /etc/rc.d/rc.mysql start
# mysqladmin -u root password 'password'

Relpace password with a real password. Then you can log in to mysql using:
# mysql -u root -p