Amateur Radio Study 

hamstudy.org – free flashcard based study system for the Technician, General and Extra.  One of the best way’s to study for your test.

HamTestOnline – web-based study software for Technician, General and Extra exams.  Tracks your progress as you learn.

Gordon West Books & Audio CDs – available on Amazon or your favorite book store.

Repeater References

repeaterbook.com – a comprehensive, worldwide, free repeater directory.