Bloomberg says that the possible antitrust inquiry Apple's facing in fact stems from a complaint by Adobe, who was most publicly cockblocked by Apple's new iPhone app development rules banning cross-compilers.
Says the Bloomberg, "The complaint triggered discussions between the Justice Department and the Federal Trade Commission over which agency should review the allegations of anticompetitive behavior, the people said."
FWIW, the WSJ indicates that the home-court advantage for iAds is also drawing the gaze of the FTC. Whatever the feds are eyeballing, it's clear that things are in motion, even if they don't amount to much in the end. [WSJ, Bloomberg]