How to move a charcter manually in Box2d?

Thanks Armitage - you are very helpful! Am I right in that you are saying you can only set the body's position when you initially define it?

Can you get a platformer up and running that has similar control to the classics - e.g Mario, Sonic etc by using forces + impulses? I am worried I will not be able to the control right using this system. I will definitely try though!

I have now also posted a thread on the Box 2D forum- which is very good.

Thanks - Rico.