I've noticed several different amounts listed various places.

My first thought would be to go to the "Free Hosting Upgrades" forum. After reading the thread at the top of the page for rules (a different thread than the link below) I can only conclude that you need 10 posts.

http://forums.bizhat.com/viewtopic.php?t=7834

However, elsewhere ("Free Web Hosting") I've seen a quoted amount of 20, which you apparently satisfy at the moment. Instructions there specifically mention PHP requests and give the format with which you should ask for an upgrade.

For mysql (your other thread) I thought that was given automatically but I can't seem to access it. Good luck!