A very observant Google follower on the Google Blogoscoped forum noticed yesterday that messing with the URL in Google Apps produced some interesting clues. Google is going to be launching JotSpot soon -- the wiki application they purchased last October.
Then Tony Ruscoe (also a brilliant Google digger) even uncovered the "Google Wiki" logo that will likely be used for the new service. You can see the (awful) logo in action on future login pages for the service.
We'll hope screenshots of the service will be leaked before the Office 2.0 Conference in San Francisco next week -- where it's expected the new service is to be officially launched.