I started a personal project last summer called AVR Remote. It is an Adobe AIR based application that works on iOS/Android and Desktop for Mac and PC. It allows, via WiFi or wired Ethernet full control over the vast array of features of Onkyo and Integra AVR’s (Audio Video Receivers, like you would find in a home theater) from their late 2010 models onwards. You might consider it similar to a Logitech Harmony or really nice remote control, but with a deeper feature set and over WiFi, so no line of site issues. I haven’t had the time to dedicate to it like I had originally wanted to, in order to flesh it out further and add all the various features, but the core communications and basics come together pretty quickly. So, I planned to open source it last fall and was going to release it at Adobe MAX, but I just never got around to cleaning it up and removing some dependencies that would have made it problematic to open source. I finally took a few minutes and got everything straightened out last week and released under the MIT license here on Github:
https://github.com/rmhall/AVR-Remote  Please feel free to fork it  and log issues  or contribute. The README in the repo explains a bit more about the background, and current status. I also included in the repo a small video of the iOS version running, as well as a link to a larger video on my site that demonstrates it functioning with my Onkyo AVR and home theater.
The model I happen to have is an Onkyo HT-RC270  and I really like it. I have owned Onkyo receivers and equipment before, and pretty much all their receivers built after middle to late 2010 all have ethernet capabilities built in. There were only some very basic apps out for a while when they first arrived, but quickly third parties put out some great apps, especially for Apple iOS devices. Onkyo put out there own for iOS, the first version wasn’t so great, but the new version 2 available for iOs and Android, is much nicer. My favorite, is a third party app oRemote , the iPad version in particular is really nice. The availability of these apps also put a little damper on my enthusiasm to complete the project, but I got it to a point where it does all the basics I needed. One of my goals was to have something my wife could use that was very simple and just allowed her to switch all the various input sources and volume controls – the basic essentials, something easy enough that even the kids could navigate. Compared to the remote that it comes with, the app is very simple, but accomplished that goal, and is stubbed out to handle all the other features with some further development. I also feel there is value in a dedicated desktop app – all the apps I have seen focus on mobile apps. However, I work from home, and use it all the time, and using it right from my desktop is really handy. Since it’s all done over WiFi and the Onkyo devices support more than one Zone of active speakers, finishing up a desktop version still has some appeal and usefulness.
I started this project just before Adobe released Native Extensions for Adobe AIR  and so I had planned to use that for a portion of the project as well. Adobe AIR for mobile does not currently support UDP sockets, nor does it support broadcast addresses over UDP or TCP, on either mobile or desktop. That is unfortunate as those two features would allow for UPnP style device detection automatically. Right now the app requires a manual input of the IP address, but a Native Extension for AIR to handle the UDP sockets and broadcast address functionality would give it the full capabilities to do the UPnP style auto-discovery of the device. I think this would be a valuable Native Extension that could be used for other projects as well. Something I may spend some more time on – and if anyone is interested in collaborating, feel free to drop me a note.