Design Basics:  http://www.designbasics.com/home/index.asp
Nelson Design Group:    http://www.nelsondesigngroup.com/homeplans/collections.php
Southern Living:  http://www.slhouseplans.com/
Frank Betz Designs:   http://www.frankbetz.com/homeplans/
William Poole Designs:  http://www.williampoole.com/
Bob Timberlake Designs:  http://www.bobtimberlake.com/shop.cfm?deptcode=78&level=2&bonus=home_tour&topcatcode=
House Plans.com:  http://www.houseplans.com/
PBS Modular NC: www.pbsnc.com