Here's a little fact, the first black QB played for Mich St. and than the Chicago bears in 1953.
And I don't know if you guys are talking about starters or just black QB's overall, but the number would surprise you I'm sure. Right off the top of my head I can name 6 blacks that are starters. Leftwitch, Vick, Culpepper, McNabb, McNair, and Brooks. And there are several more that are backups. Off my head I came up with Tony Banks, Charlie Batch, Jeff Blake, Anthony Wright, David Garrard, Jason Cambell, Senica Wallace, and Shawn King. So thats atleast 14 black QB's that are playing right now.
The harder question to ask yourself is can you name even 1 NFL running back that is White.