Programming:WebObjects is a new Wiki Book chock full of WebObjects topics. It’s content, much of it culled from the webobjects-dev lists, is coming along nicely thanks to the amazing work by Mike Schrag.
It is a great resource. Link to it, use it, expand it.
Update: Mike posted that the (updated) content of wodev.com (maintained by Pierre Frisch) has now been migrated into the new Wiki Book as well.