My daughter gave up her last nap around that age, though the average child still naps once a say for a couple more years. The first thing I would do is move his bedtime earlier. When my daughter stopped napping I moved her bedtime up to compensate. She is 3 1/2 yrs old and is ASLEEP by 6:30pm most nights and wakes between 6:15am and 7am. Make sure to keep the bedtime flexible, depending on morning wake up time, nap, and general attitude. You may find he will start napping again if you move bedtime at least 1 hour earlier and try putting him down for a nap around 1pm instead. I HIGHLY recommend getting Healthy Sleep Habits, Happy Child by Dr. Marc Weissbluth for age appropriate sleep needs and schedules.
Sincerely,
L.