Audio Commentaries from BYU Broadcasting: (These commentaries are awesome!  You can listen to them on your windows media player, mp3 player and it shows you the next time you can watch them on TV)

Book of Mormon
Doctrine and Covenants
New Testament
Old Testament



Gospel Doctrine Resources from Bella Online
Gospel Doctrine teachers and all Sunday School teachers
LDS Gospel Doctrine Net
LDS Living - Scroll down to whichever book of scripture is being studied
LDS-Seminar : An e-mail list you can join, intended to be a resource
Teaching Helps for Gospel Doctrine Teachers
James E. Neumann's Gospel Doctrine Website
The Gospel Doctrine Class