Appleinsider points to a recent Apple patent which describes a "wireless touch-screen remote control concept that would automatically discover and communicate with existing and future consumer electronics appliances as well as the personal computer"
The patent was filed in April 2002 and describes a device which "discovers" potential devices to be controlled by the remote. Each device (such as a DVD player or iTunes app) need only be discovered once. A special XML interface would provide the remote with the interface controls to each individual device. Such technology would allow the remote to be truly "universal" without needing any prior knowledge of the device to be controlled.
Such a system would require standardization amongst electronics manufacturers to incorporate this "discoverable" remote control system to become useful.