Here's an easy way to find all of the important stuff we have to offer:
Teacher and Troop Megalist - an giant list by country and state
Costumes and Accessories - some good sites to find the perfect get-up
Useful Links - random sites that have a lot to offer
All of these sites will be continuously updated as more sites are found. Feel free to send a message with your own favorite sites so that we can add them! If you find any of the links to be broken or incorrectly organized, please let me know. I want to keep this as up-to-date as I can, but it is a LARGE list, and therefore I am bound to miss things.
Also, before suggesting a piece, please read the Submission Guidelines!