Yamaha has 3 receivers that are IP controllable. They also have an iphone app for these three apps.
RX-V3900
RX-V2065
RX-27

Also Direct TV is adding IP control to several of their boxes. This is very Beta currently. See discussion at dbstalk in the cutting edge forum. (This is a hidden forum, registration required).

I've seen reports that TIVO, series 3 and Apple TV are IP controllable.

Remember, just because a device has an ethernet port, doesn't mean that it is IP controllable. Several Blueray players are internet connected for netflix and pandora type services, but are not IP controllable.