A setti sheet is what the character designer 
makes for the rest of the staff to base their 
drawings off.  There will be dozens draw up for a 
show/movie, several of each major character in 
various poses, outfits, etc.  This is so that the 
animators can draw the characters consistent with 
each other since the character designer can't do 
all the animation himself (though he will 
sometimes surpervise the animators and make 
corrections).  I've got a couple on my webpage if 
you want to check em out:

http://www.kimonocels.com/Original_Art/Pre-
Production/pre-production.html

Cheers,
Brian