When iTunes Radio launched last fall, the service was designed for music fans (and music labels). Now it is branching out: National Public Radio is adding the first news station to Apple’s audio streaming service, with more on the way. NPR’s station, which should be live today, will offer a free stream, 24 hours a day, which mixes live news with segments from pre-recorded shows like “All Things Considered” and “The Diane Rehm Show.” NPR officials say that within weeks, some of the broadcaster’s local stations should begin offering their own stations, with a similar mix of live and taped news. And since NPR’s executives have previously talked about plans for a mobile app that would generate on-demand programming that would change based on a users’ listening preferences and location, it’s possible a version of that service could migrate to iTunes Radio down the line.