Just waiting on Sling...
http://www.slingmedia.com/go/iphone
And yes, last time I looked,
ATT's contract prohibited apps like Sling. Although I suspect they just look the other way when it happens on WM and RIM phones, unless it swamps them.
"... downloading movies using P2P file sharing services, redirecting television signals for viewing on Personal Computers, web broadcasting, and/or for the operation of servers, telemetry devices and/or Supervisory Control and Data Acquisition devices is prohibited.
"Furthermore, plans(unless specifically designated for tethering usage) cannot be used for any applications that tether the device (through use of, including without limitation, connection kits, other phone/PDA-to computer accessories, Bluetooth® or any other wireless technology) to Personal Computers (including without limitation, laptops), or other equipment for any purpose"
So the iPhone will need an exemption, unless ATT changes the wording.
Interestingly, Verizon dropped the TV prohibition in their contract when they came out with their $30 smartphone data plan last Spring.