ITC staff lawyer, Erin Joffre clarified the ITC's position at the start of the ITC hearing in Washington just today. Apple claims that phones made by HTC and Nokia are making unauthorized use of their IP. They point to all manner of user interface and hardware features, even esoteric ideas like power management for mobile chips.
The ITC staff acts on behalf of the public to mediate trade disputes, so its recommendations are not binding. Although, they do carry weight. It's too early to tell how this will work out, but it's probably going to be years before we see a resolution.