Jamboree on the Air Thought Starters provides ideas to help prepare Scouts for Jamboree on the Air. The information has been compiled from years of JOTA participation.
JOTA Activity Booklet is provided by Alan Wentzell, KE4TIO, of Pack 415 in the Gulf Ridge Council, the booklet introduces a great deal of information and includes some games that Scouts will enjoy.
Finally, some resources provided by ICOM America, a series of comic books written for Scout-age youth to introduce amateur radio concepts. You can download all seven of the comics at here.