Wikiseek - New Search Engine for Wikipedia
Wikiseek – located at wikiseek.com and launched in January 2007 – is a new way to search Wikipedia. Wikiseek searches only Wikipedia and external Wikipedia links. Because these links are selected by the Wikipedia community, Wikiseek search results are likely to return more relevant results for many searches.
Also check out Wikiseek Community wiki.
I simply love wikipedia, and it is one of my primary source of information on encyclopedic articles, but do know that at times even this great portal/wiki may have wrong/not up to date information, so be sure to check few more sites/printed materials on information that is of interest for you and relevant to your queries.