Animation
General
This massive site has news, articles, forums, galleries, business databases, everything. It can be a bit confusing to navigate due to the sheer number of pages, but there's a lot of good information in there.
Maintained by animation insiders Amid Amidi and Jerry Beck, Cartoon Brew has consistently good coverage of the animation industry.
General animation news roundup.
All Things Disney. Great blog.
In light of Disney's recent acquisition of Pixar, the differences in news between the Pixar Blog and the Disney Blog are likely to evaporate.
All around blog for traditional animation.
Animation Meat has some unique resources for animators, such as storyboard templates for TV and film and lecture notes from many well-known animators.
No animator should be without this book. It is not only essential for learning, but is great for reference as well.
Personal Blogs
Most famous for his Ren & Stimpy animation, John demonstrates how to create awesome caricatures.
Tinsleman's Robyn Miller created the art and animations for numerous Cyan games, including The Manhole, Cosmic Osmo, Spelunx, and, most famously, Myst.
Stop Motion Animation
The forum on this site is incredible. It has dozens of sub-forums on topics ranging from foam latex puppet fabrication to homebrew motion control camera rigs.
This site contains everything you'll need to know to build models and armatures, animate, and film a stop motion short.
A cool overview of building a wire armature. Wire armatures are generally only used for small clay characters. They're cheap and easy to build, but they can be difficult to pose.
Ball and socket armatures, a much more robust solution than wire, take incredible skill patience, and money to build. They are generally used for puppets fabricated from foam latex (also a very labor-intensive process).
A handy guide to the dozens of polymer clays available.
Computer Animation
As I type this there are 1,783 active users participating in this forum, with a total of 202,916 registered members. There are 55 sub-forums covering every possible topic related to CG, many of which are being viewed by 100 or more people at any given moment.
This is the place to be for computer character animators.
The main draw of this site is their monthly contest: a 10 second clip of dialogue is provided, to which one must animate.
Keith Lango has some awesome tutorials for character animation. Especially worth noting is his introduction to the pop-through technique for blocking and then refining animations.
A long and varied list of links from Carlos Baena, a Pixar animator.
These notes, compiled by Shaun Freeman, hold the collective knowledge of some of the greatest modern animators.
Software
This software replicates in all of the tools used for traditional 2D cel animation, from sketching to inking to painting.
PAP is essentially a pencil tester, a program for doing quick sketches and seeing them in motion.