I'm surprised no one has pointed this out yet:
http://opensourcecms.com/
They have test admin and user accounts on most major open source CMS, CRM and blog packages.
Usually, they will say to use a LAMP stack, but you should be able to use OSX just fine.
Don't forget to included mod_php in apache, or apache won't be able to use php. Unless the PHP installer already does that for you? I'm not sure.