Apparently some of the content in the iTunes store (from what I can tell, only the HDTV shows) have HDCP which means that if you want to connect one of those brand new MacBook, MacBook Pro, or MacBook Airs to a non-HDCP compliant display that uses DVI or HDMI your not going to be able to watch that content on that display.
I’m not sure if there is a way around it, I would guess that since the HDCP is ignored if connected to a VGA display you could get a DisplayPort to VGA adapter and then a VGA to DVI adapter which could (possibly) make your computer think that it is connecting to a VGA monitor and not a DVI monitor and therefore ignore the HDCP flag, but since I don’t have the hardware to test it I can’t say for sure if that will work.
Regardless of whether or not there is a workaround this is a problem and I don’t know if Apple is ever going to fix it, since the limitation is put on the media because of the content providers Apple will most likely tell consumers to complain to the media companies and not to Apple.
I just wish that media companies would stop treating regular joes as pirates and understand that the ones they really need to stop (you know, the guys who are selling pirated copies) don’t have any problem getting around this restriction and therefore is pointless in the “war against piracy.”