Motorola are trying to get Microsoft to either pay up licencing fees or stop selling the 360 on grounds that the latter are infringing on patents owned by the former. And, what's more, Motorola are probably in the right, at least if a preliminary ruling is anything to go on. The final ruling won't be given until later in the year, but it sounds like Microsoft are more than willing to fight it.
"Today's recommendation by the administrative law judge is the first step in the process leading to the Commission's final ruling," Microsoft said in an email to AFP. "We remain confident the Commission will ultimately rule in Microsoft's favor in this case and that Motorola will be held to its promise to make its standard essential patents available on fair and reasonable terms."
Patents are infringed all the time and it's usually as simple as paying a fee and getting on with things. Until at least the late eighties, the Pong game was under patent and everybody that made a game similar to Pong needed to pay a fee. I suppose we'll see how this plays out over the coming months.