To help myself and others review Nehemiah, I recommend this resource from Luther Productions.
Other resources I often use for on-line research include Wikipedia, and the Catholic Encyclopedia. Since Wikipedia is an "open-source" encyclopedia, it's important to remember that it isn't juried in the same way a regular print encyclopedia is. Some may consider this a more authentic intellectual approach in any event.
Finally, there's the Catholic Encyclopedia. This is often a very helpful resource, if a bit dense.