L.M.
This one is sooo easy! My son was 6 when he learned, but we took him to a grassy spot that was sloped downhill, gave him a running push for a bit, and then let him go!! I don't even think he fell at all because the balance instinct just took over. Just make sure to keep yelling "pedal, pedal, pedal!" The faster he goes, the easier it will be. If he falls, he's not going to get hurt. If he falls and is scared, be sure he gets right back on and tries again. And to Suzi who said not to teach kids to ride a bike because it's too dangerous??? Her poor, poor children. That's all I can say. How sad.
The smile on your child's face when he learns to ride a bike is absolutely priceless.