http://www.searchtheweb2.com/

This new service identifies the common and not so common word combinations that occur in results for the query. "...Not sure what search terms to use? This engine shows you all possible variations of a query from common (trendy, popular head) to obscure terms (long tail) and lets you narrow your search using these variations. Thus, SearchTheWeb2 is unique, it is not only used to search The Long Tail but also to improve the relevance of search results using long tail refinements...". More information on Internet News.