Today (19-March-2007) Adobe? released the alpha version of Apollo the runtime technology who promises to let you build cross-operating system desktop aplications using your hard earned existing web development skills (Flash, Flex, HTML, JavaScript, Ajax).

Here’s what they say about it:
Apollo enables developers to create applications that combine the benefits of web applications ? network and user connectivity, rich media content, ease of development, and broad reach ? with the strengths of desktop applications ? application interactions, local resource access, personal settings, powerful functionality, and rich interactive experiences.

You can check it out at:
http://labs.adobe.com/technologies/apollo/