John's still working on the mockups of various top-level pages, but I envision our FAQ to be a lot like the one at UNT Libraries here.
We still hope for it to include both textual answers and short screencasts, but the UNT site gives a pretty good illustration of the general set-up and categories.
A working prototype of this will be among the first things created once our Drupal instances are in place and the site starts coming together. This is definitely something that we'll need a lot of input on from just about every group in the Libraries.
If you have other ideas about the FAQ/Knowledge Base, let us know in the comments or send me an email!