For my own future reference:

Tim O’Reilly checked with Cory Doctorow who checked with Lorna Toolis who checked with Barry Wellman who checked with Ren Reynolds and Ellen Pozzi who point out that there’s an NPR Talk of the Nation broadcast from 1999 where Gibson says, “As I’ve said many times, the future is already here. It’s just not very evenly distributed.”

The actual citation:
NPR Talk of the Nation
30 November 1999
Timecode: 11min 55sec
Link: discover.npr.org/features/feature.jhtml?wfId=1067220
Also: http://www.npr.org/rundowns/rundown.php?prgld=5&prgDate=30-Nov-1999

(Via Brainstorms.)