A meta search engine is one that queries other search engines then returns results.Some examples are Dogpile, Mamma, Vivisimo, Katoo & MetaCrawler. How good are the results? Well check for yourself at the end of the day for best results just use a normal search engine.
More info can be foud here:
www.lib.berkeley.edu/TeachingLib/Guides/Internet/MetaSearch.html
