A group of students from University of Toronto "have completed something that could potentially replace all the remotes you have scattered around the house". It's called Universal Infrared Remote (UiRemote). It is currently available only for iphone.
Using this application on iphone, you can control anything that can be controlled by an infrared remote. You can also teach it to "learn" any buttons, or button combination macros, of any standard remote.
UiRemote works by using a custom infrared adapter that plugs into the phone’s headphone port. At the time of writing, the application is still in its beta stage. You can find out more about this application at http://uiremote.wordpress.com/ .
