Feeds your search terms to many search engines
Aggregates results and presents most likely matches
Can run in background or in batch mode
A further option is to find a meta-search engine, which will take your search terms and feed them into many different search engines, then collate the results . Sites such as DogPile use a web interface and server-based scripts to send your query.
Meta-search engines are particularly useful when deciding on a search engine to use extensively, as some allow you to compare results from each of the searches, giving you an at-a-glance view of the most effective engine for that particular search term. However, as they feed the same query to many different sites, they may not produce as detailed or specific results as using a single search engine with a detailed, accurate search query.