I haven't found any online info that would be helpful. However, I have the NDS 2005 Wood Design Package, which looks like overkill, and the Kaplan Review manual has a Wood Structure Design section and a Timber Design section in it. I don't know if that helps you or not.
According to the NCEES outline, timber is a subcategory under one of eight topics in the Other Topics section. Statistically, there is less than a 2% chance it'll show up on the exam. I don't plan on spending a lot of time studying it and am willing to take my chances with guessing. I may regret that if it happens to be the one question that pushes me over, but I plan on being prepared for the other 98% of the exam. Good luck on the exam.