I've added a weeniepedia search to the forum, immediately underneath the regular search box in the left column. It's version 1, the alignment is not perfect particularly on Opera & IE6, will fix.
So if you type a search term into the weeniepedia search box the wiki search results will open in a new browser tab in the current tab.
[later: I think it works better to make it open the wiki results in the same tab, particularly with Safari which insists on starting a new browser session. You can hit the back button to navigate back to the forum]