Adobe AIR is a cross-operating system application runtime that allows developers to use HTML/CSS, Ajax, Adobe Flash and Adobe Flex to extend rich Internet applications (RIAs) to the desktop.
Google just launched a week ago Google Gears another technology to extend web application to the desktop. Adobe AIR along with Adobe Flex (see separate press release for Adobe Flex 3 public beta, also available today) are cornerstones of Adobe’s comprehensive RIA platform. Adobe recently announced its intention to release Adobe Flex as open source.
The beta version of Adobe AIR and the Adobe AIR Software Developer’s Kit (SDK) can be downloaded for free from Adobe's site.
Adobe AIR and the Adobe AIR SDK are available in English and offered for both Windows and Macintosh operating systems, and future versions will be available for Linux as well as other languages.