I'd like to do the same thing, but I'm a newb to all this web hosting stuff. The fantastico is working out very well, but mediawiki isn't offered in it.
Perhaps this could be remedied? Seeing as media wiki is open source and all. I tried tikiwiki and did not like the syntax. The phpwiki looks horrible and I have a media wiki backup xml I'd like to import. Oh admins please save the day and add mediawiki to the fantastico.