Video:
Total Training – Expensive, but extremely comprehensive.
Lynda.com – No experience with this myself, but others recommend it. You can apparently buy a subscription for as long as you want.
Books:
After Effects Classroom in a Book – Probably the best option for somebody starting at the basics.
Creating Motion Graphics with After Effects – The comprehensive, authoritative guide. Starts with the basics, but the book is more about learning the fundamentals than getting your hands dirty and practicing with the program. Once you learn the basics, this series will be your bible.
There are some other good books out there, but off the top of my head I can’t think of the titles. Others might make more recommendations.