When I move the my rig, it shows duplicate parts of the model I've started following this guide for modelling in blender, but have come across a problem when rigging. I've rigged everything and it works just fine to move some parts, but when I move my arm a duplicate arm shows up, unmoved! This also happens if I move the rest of my rig, it will show a duplicate hip, neck, and ankle joints!

My guess is that I somehow double modeled these parts maybe? I'd provide more pictures but since I'm new to Stackexchange I can't post more than 2 links.
I have no idea what I'm doing :O please help!
Nevermind I think I fixed it -- the joints that were not moving weren't bound to the armature, and the extra arm I just deleted by using "l" to select it and then deleting it.