Peterson, who turned 34 on Thursday, is one-shot clear of Stan Utley (67), Bo Van Pelt (68) and R.W. Eaks (70).
The 48-year-old Eaks led after each of the first two rounds; and would have held a share of the 54-hole lead, but bogeyed the home hole.
Eaks, a three-time tour winner, recorded seven birdies and five bogeys in the third round.
Peterson was much more steady, posting five birdies and no bogeys. The former Georgia Bulldog, who won the 1995 Buy.Com Central Georgia Open, made the turn in 4-under 32, and then cruised home with one birdie and eight pars over his final nine holes.
In the Pro-Am division, which ended on Saturday at the Cliffs Valley Golf & Country Club in Greenville, SC, actor Kevin Costner and Brian Hull took home the top honors.
Hull and his partner/sponsor shot better-ball rounds of 58-63-64-185 to finish the event at 31-under-par.
Hull could use Costners handicap on Sunday. Hes 1-under-par entering the final round.
Full-field scores from the Buy.Com Charity Pro-Am at the Cliffs