Nielsen's new national survey of U.S. mobile phone customers reveals that smartphones are outpacing traditional feature phones for the first time ever.

According to the May survey, 38% of all mobile phone owners now use a smartphone. And within the last three months, 55% of new phone purchases were of the smartphone variety (that's a 34% jump from just last year). The Android OS continues to be the most widely distributed, with a 38% market share. [via Nielsen]