The Wall Street Journal ran a story on Friday ranking college football programs by their current alumni presence in the NFL. UNC came in 10th, ahead of Notre Dame, Penn State, Nebraska, Penn State, and Southern Cal. Some of that's a factor of the years it takes to really make an impact in the NFL, as most of the players listed are Mack Brown recruits - you'll recall the turn of the century wasn't the greatest time for a lot of the programs listed above. Still, it's a proud accomplishment for the Heels.
(Database Football has a list of Tar Heels in the NFL up to 2004 and Wikipedia a a list of notable alumni, but there's no canonical list to try to replicate the WSL's results.)