Here again the online apologetics and discernment work Apprising Ministries gives you these two items, which seem to keep moving around their websites and/or suddenly disappearing.

John Piper Interview Pastor Rick Warren Transcript

See also:

JOHN PIPER, RICK WARREN & FOSTER-WILLIARDISM

SADDLEBACK CHURCH OF RICK WARREN USING ROB BELL TEACHINGS

IS THIS DOCTRINAL AND SOUND DR. JOHN PIPER?