In reply to Big Jim The Climber:
All kids are different, but don't expect too much. My young kids get bored after 20mins. Bouldering and traversing is best. They often get scared climbing even a few feet up. That's not a bad thing to be honest. Biggest problem is lack of holds between 1ft up and 3ft up for actually climbing upwards. Kids can use tiny holds, but there's a gap in this range on lots of routes. Ignore the grades and colours, 3's etc are designed for older kids in trainers not short kids only capable of a small step up.
Don't expect to get anything useful done yourself, unless you have someone else with you. Some walls are good for this and don't charge for a supervising adult.
Steve