Last year, Google released a mobile app for iPhone that lets you search many data sources from a single location: web pages, local businesses, contacts. A similar application is now available for Mac OS X 10.5 Leopard and it's called Quick Search Box.
Nicholas Jitkoff, Quicksilver's creator, is one of the developers. The application is a powerful box that works as a program launcher, address bar, Google search box, desktop search box, calculator and weather gadget. The source code includes modules that integrate data from Google services like Google Bookmarks, Gmail and Picasa Web, so the application has the potential to become the central point for accessing Google.
"For the last year, we have been working on a new, open-source quick search box. Today, we are releasing our first developer preview for the Mac. This Mac version is much more experimental than its iPhone sibling, Google Mobile App, and through it you will be able to see many of the areas we are exploring: contextual search, actions, and extensibility. It is by no means feature-complete, but is a very good indication of things to come," explains Google.
Quick Search Box is also a feature of Google Desktop, but it's unfortunate that Google didn't integrate more data sources. My favorite Windows Vista feature is the ubiquitous search box. Some interesting alternatives are Launchy, an extensible application launcher for Windows and Linux, and Mozilla Ubiquity, an experimental project that makes web applications more useful. All of them are powerful command-lines that expose information from your computer or the web.