Here's a link to all four Wilton cake preparation and servings guides:
(Gives batter requirements by pan size, as well as recommended baking temps. and times and party or wedding servings by pan size.)
http://www.wilton.com/cake/cakeprep/baking/times/index.cfm
Doug has provided wedding servings help thread for sheet cakes:
http://www.cakecentral.com/cake-decorating-ftopict-591535-.html
Indydebi does the math for 2x2 and 2x3 servings from single layer sheet cakes:
http://www.cakecentral.com/cake-decorating-ftopict-302303-.html
HTH
Quote by @%username% on %date%
%body%