wiki.is provides free Devi Wiki hosting.

Simple to setup, just provide a name for your wiki and an email address to mail the admin info to you and your done!

The UI is quite friendly and the you don't really have to mess with markup language like in MediaWiki. Still playing around with it though.

From the webpage seems like you will be able to do some sort of mashups with google and yahoo.

The free version provides up to 100megs of space while the pro version gives you 10 gigs and cost 10USD a month.

Links
Comparison between Free and Pro