Everything what concerns Adobe AIR, formerly known as Apollo, is in beta but despite this amount of applications already done or announced using AIR amazingly increasing. So now it seems that AIR will compete successfully with Dekoh or WPF and at least not share sad end of it’s precursor Macromedia Central.
Recently I have found on Rayan Taylor’s blog an article about nice application for mixing sounds made in AIR and Flex. In DigiMix you can put some sounds loaded from your disc on different tracks, trim beginning or the end, add some effects and finally save your project or even compile one wave file on disc.DigiMix has some limitations eg number of loaded files and it accepts only 16bit 44,1kHz wave format, but this is beta, and what is essential - it works with wave files natively not supported by Flash. This application truly shows capabilities of Action Script 3 and AIR.
For those who know almost nothing about AIR this is a technology which allows you to develop cross platform desktop applications. To run the application, which has .air extension, first you need to download and install AIR runtime environment. For now AIR is accessible only for Windows and Macintosh. There is also beta update to Flash CS3 which allows to package and preview AIR. I think that final release will much more popularize this technology. At last, remember everything is in beta ;)

Related links:
List of AIR applications
Adobe AIR Showcase
Download Adobe AIR
DigiMix