This free reference tool from Answers.com can look up quick answers in a range of authoritative sources, while you're working with any application.

Customizable free metasearch tool which queries many engines, removes duplicates, and validates the results.

A suite of tools for searching the internet using multiple engines and resources at the same time.

Customizable desktop software for Windows that searches multiple search engines and websites simultaneously. Freeware and trialware versions available.

Gratis metasearch software that queries several web search engines, accesses found web pages, and crawls their links. Free download.

A free tool to search and download MP3 files from the Net.

Free dockable web search toolbar that can launch searches in myriad search engines from many categories. Includes automatic translation and can be extended with more search engines.

Open-source, browser-based application that searches the user's history of viewed pages.

Desktop client which offers browserless Internet meta-search. It searches any text already on screen (or manually entered) and retrieves collated results.