Firefox 3 has a nice little Address Bar which many like to call AwesomeBar, it can be used to show you results as you type from your history and bookmarks.
CyberSearch takes the awesome bar to another level by allowing you to search Google, Wikipedia and several other sources which you can add yourself by using smart keywords from within the Firefox Address Bar.
For example if you want to search Google for a particular term, you can search by using gweb your keywords, you can also use gblog your keywordsto search using Google Blog search. There are several other searches you can perform with ease using predefined keywords, the search experience can be customized by creating you own keywords.
CyberSearch is based on AwesomeSearch (now Firefox extensions,awesomebar,cybersearch,search from firefox address bar