I use
awardspace.com Is adfree and supports PHP and MySql (1 db only
though). I use it for wiki stuff and my two are at
http://wikimania2007.awardspace.com/ and
http://wnirc.awardspace.com/ .
Havent used for a wiki but Is totally free, great uptime and allows 5GB of
traffic, havent tried the customer service though and doest have a very
good web editors though does allow FTP uploads.
Would recommend allot.
Mark