if you are looking to host a small site, i would recommend check out www.mxhub.com . 1000MB space and 40Gb transfer at 7.95 per month. with a free domain name when paid annually. Their support had been excellent for us.
PHP files can go anywhere on a web server that is running the PHP Server Module. If the web server is not enabled to host PHP pages then they will not work. I found a list of free php web host here.
Have you actually tried registering to those sites? I've found a lot of lists like that, and they usually tend to have hidden charges or some stupid catch that makes you cough up money. Some out them were outdated and no longer offer free service, but of course they only tell you that after you've registered.