I searched the forums and didn't see anything on this topic, so I want to pose to the forums if anyone else is seeing issues with this. I have the 3GS, not jailbroken, running iOS 4.3.1. I have been using Nike+GPS lately (latest version), and for headphones, using the Motorola MOTOROKR S305 Bluetooth stereo headphones. It used to work well, but ever since iOS 4.3, the music skips around like crazy, as if the processor is not able to keep up. It makes me MENTAL when I'm pushing myself through a hard run and the music keeps jumping around. The audio is just broken. It's not just the music, too, it's the audio cues coming from the Nike+GPS app. The only other note is that although I was running outside with a clear view of the sky, I kept getting a pop up stating the GPS signal was weak. It was very overcast and cold, so perhaps the cloud cover was the issue--and perhaps the GPS app just doesn't work well or is clearly using tons of CPU resources if it's searching for a satellite.
Last note is that I don't ever have this issue when using the headphones when sitting still, on the iPad and 3GS. Thoughts?