Sprint replaced my Curve because the audio kept switching back and forth erratically between the headphones and external speaker. Then it quit working completely. Now the replacement is doing the same thing. The problem is not the headphones because I experienced the same issue with 3 different sets that work properly in other devices. Has anyone else had the same problem?

My curve did the same thing. A few days ago I got a Tour... and it does the same thing. New phone, new headphones (that came with the Tour). I used the headphones on my friend's Palm Pre and they seemed to work fine. I think Blackberry's audio jack design must have some issues.