The Injection Flush, as well as the Induction Carbon Cleaning, are relatively new for the 6.0, at least around here. The Injection Flush is a process where they hook up a machine to the engine and pump either BG or Wynn products in, and it's supposed to get all of the crap out of the system.
The Induction Carbon Cleaning is a really cool procedure where they put product in the intake and you literally get a pile of soot coming out of your tailpipe. Guys on Powerstoke.org and Dieselstop.com have been talking about it. Power and mileage gains have been reported.
I spoke to my local dealer and the price of a BG Induction Carbon Cleaning is $309, which includes a mandatory oil change....I didn't get a price on the Injection Flush. Both the Flush and Cleaning require an oil change, due to the fact that the chemicals seriously break the oil down and would damage the engine without it.
Hope that sheds some light.