You've got to start riding a motorcycle sometime, so why not start them when they are really young.
Kiddi Moto in the UK offer a wide range of motorcycles for very young kids. All the motorcycles are made out of wood, and are real "push" bikes, ie, no pedals. They are pure play things. Great for getting your kids used to two wheels.
They have four different types of motorcycles:
-Scooter, -Chopper, -Scrambler and -Superbike.
Each type comes in a large variety of colors. But for a few pounds (money that is) you can put your kid's name on the bike...