Firefox: Omnibar Extension Integrates Firefox’s Address and Search bar into one single box
For Windows, Linux and Mac: The Omnibar extension for Firefox practically integrates Firefox’s address and search bar into one single box. This fusion gives to the Firefox awesome bar an Omnibar (Chrome) feature. With this extension you can quickly switch search engines using keywords like @live.com to search bing
Download Omnibox extension for Firefox 3 and Higher.