What we need is a wifi/wireless receiver that then shoots out IR from IR blasters like Tivo does if you have a cable box.
In a way you could now control your cable box using your iphone. I got the tivo remote app which I use to tell tivoHD to change a channel. I believe that if you have tivo series 3 that is not HD that you would tell the tivo to change the channel and it would tell your cable box to change.
What you & I am looking for is a device that would to that portion of a Tivo's job but for all of our components. Would end up being a cheap way to create a house wide entertainment system that can be controlled anywhere in the network.
FYI: They make expensive versions of what we are looking for... (ILuvControl?)