Adding Functionality to Digital Cable Boxes?

Marqis asks: "I have a Motorola DCT-2000 (info here) and supposedly it supports 3rd party software. I would like to be that 3rd party but I can't find any information about programming this unit or how the data port can be used. After phoning Motorola I was told that the data port hasn't been activated yet. Not sure how that works. Anyhow, I really hate my cable company's layout of the on screen tv listings as it only shows a 1/2 hour time block. I would much prefer a 1 hour (or even 1.5 hour) time listing that should be possible if the gigantic 'Push here for help' buttons were taken out. Also, I know from reading news groups that lots of people would like the ability to change channels through the data port so their Tivo's wouldn't have to use a sometimes flaky IR blaster. Web surfing, email checking, tv listing download, mpeg streaming to a pc and the like are also theoretically possible. Any info on the data port, protocols, compilers, etc would be greatly appreciated."