Body Parts

Several worlds include classrooms and helps of one kind or another for avatar customization.
jetjanitor's body diagram
JetJanitor's Jet City Life - Classroom Body Diagram

Codes for Body Parts

L - Left Upper Arm
R - Right Upper Arm
M - Left Forearm
U - Right Forearm
O - Left Hand
V - Right Hand
I - Left Thigh
W - Right Thigh
J - Left Lower Leg
X - Right Lower Leg
K - Left Foot/Shoe
Y - Right Foot/Shoe
B - Upper Body
P - Hips/Dress
N - Neck & Head
Z - Tail (creature and birdie only)

Default Color Meanings

a - Skin Color
d - Dress Color
b - Shirt Color
e - Pants Color
c - Coat Color
f - Hair Color