Its going to be a 3 tiered cake. From bottom tier 10 inch double layers, 8 inch double layer, and topped with a 6 inch double layer.

I'm making my cousins 1st birthday and I'm rather excited. I had trouble picking out what I wanted the cake to be but finally settled with "Toy Story" and his birthday party is the same day Toy Story 3 comes out

I have a question does anyone know how to make crators in cake. This cake will be covered in fondant. If this cake is a success it'll be great news for me . Any tips and advance will be highly appreciated

a 10" 8" and 6" round stacked layers will feed 74 .

remember it depends what size you cut the slices. 10-8-6 is 74 wedding servings, 9-6 is 44 plus whatever the 4 inch works out at (very fiddly to cover small cakes remember).
http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm
party sizes, the 10-8-6 is 60 servings, the 9-6 is 36, plus say 4 from the 4 inch.
http://www.wilton.com/cakes/making-cakes/baking-party-cake-2-inch-pans.cfm

remember, you could always buy a dummy tier to make up the size you want without so much actual cake.
xx