Hi Jeremy,
Here's some sample code that will apply a texture to the male's torso. The problem is creating the shirt texture so that it aligns perfectly onto the avatar. If you just want to change the shirt to a solid color, then you can just create a texture of a solid color and apply it to the avatars torso.
Code:
shirt = viz.add('shirt.jpg')
male.texture(shirt,'m_torso_LS.cmx')
To make this work for the female you will need to change
m_torso_LS.cmx to
m_torso.cmx.