Kristy Duncan-Johnson and Jeff Rank worked closely with the Media Center Team to develop MSN Remote Record using the same, exact API set available to all third parties. Learn more about it over at Channel9 Videos.
MSN TV - Bringing MSN Services Into The Living Room
Another great resource if you want to read about MSN Remote Record is Schedule TV Show Recording over the Web Using MSN Remote Record Service by Microsoft MVP Justin Harrison.
And finally, the methods and properties used by MSN to develop MSN Remote Record are located in the Windows XP Media Center Software Development Kit (SDK) starting with the Click-To-Record Feature topic.