Saw this in a thread in the HTC Desire forum, so I thought I'd post it here. There's plenty links in that thread (articles and blogs), so you can get them there. The download link is in post #17 of that thread. After I installed the app, just tapping on a file in Astro didn't give me the option to use "demoPlayer" however. I had to fire up the app, then navigate to the file I wanted to play. Works pretty good for an app that's in beta. As usual, it plays some filetypes better than others. I also use "Meridian Media Player Pioneer" (in the Market) for those files.