My googling for search engines led me to choosing the following three:
SearchMash (http://www.searchmash.com/), a search engine operated by Google Inc.,
Dogpile (http://www.dogpile.com/) which, according to their policy, combines the sponsored, clearly identified, with non-sponsored web search results, depending on the typed search keys, and
Snap (http://www.snap.com/?source=google&campaign=snap&user_keyword) which wants to offer an alternative to the leading search engines, by introducing a few useful features like: results preview, anticipating one's intent, direct interactivity with the search results, and faster speed.
Although some search results were similar when typing "wikis education" in all three search engine, I think the best results were provided when using SearchMash. All first 5 results contained both search keys: "wikis" and "education" and all the websites found contained relevant information according to the search topic/words: Educause, a magazine that deals with the latest developments and trends in information technology and its' application in higher education, an Enciclopedia of Educational Technology which is a very informative site of the Educational Technology Department at San Diego State University, a website with resources about blogs, wikis, podcasting and their use in the classroom, an entry to the wikipedia, and a webpage with interesting resources in German, English and French about wikis, even though this site has last been updated in October 17, 2004.