Getting MySQL working with PHP from a booted CD:

Copy the contents of /etc/apache/httpd.conf to a new file, delete the old one (it's actually a symlink) and save the new one (after you have edited it to enable PHP) under /etc/apache/httpd.conf

Then run

/etc/init.d/apache start
/etc/init.d/mysql start

You can even install Webmin to make things easier...
Btw, for a server you might want to boot with

knoppix 2

to get rid of the graphical stuff...

probono