For detailed information for your cub's level of scouting, please check within his book. Books, uniform pieces, patches, activity kits and equipment are available on-line through scoutstuff.org, Camp Tadma trading post, CT River Council stores and at local scout suppliers.
Below are some handy sites that can help along the way.
National BSA
Scout Parents - basic information for each level plus helpful information to make the most of the program.
Other Awards
Individual Program Information outlines & some links for requirements (note, these are not necessarily BSA sites)