I think this is the prettiest and simplest way to do it.
<img src="http://dl.dropbox.com/u/32679138/thumbstick.png" border="0">
Set a drag object, and use the angle between it and the "thumbstick base" to set the angle of motion.
You can definitely be creative and add the running/walking control by either adding separate base,
or just by calculating the distance between thumbstick and the base.
Eg,thumb is dragging-->playerbox move distance(thumb.x,thumb.y,base.x,base.y) / "Insert your number here"
Capx
Simpler, Neater, offering precised control, and offer easier customization.
P.S.: I guess I done my little part to contribute to this forum =P
I will appreciate someone else spend some time to teach me all the expression and tricks about multi-touch~!(No the manual and tutorial is not helping at all)