I've been trying to do some research on the war (now that I'm through with finals), but every website I've encountered tends to cover it in one page, treating it as nothing more but a precursor for WWI. :(

The Franco Prussian War: German Conquest of France in 1870-1871 by Geoffrey Wawro.

Google books has a preview of it. If that doesn't work try other Google Book searches.

Of course there is always Wikipedia, but that may not be useful if you plan on writing a paper on the subject.

http://books.google.com/books?id=Y1T_GET-R1cC&printsec=frontcover&dq=franco+prussian+war&hl=en&ei=KZ2CTfjcGo240gGBlujGCA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCgQ6AEwAA#v=onepage&q&f=false

I know this is a necro, but if you want a decent account without a whole lot of wrangling about historiography and such, don't use Wawro's book. Please don't use Wawro's book. Combine Showalter (2004) with Howard. Read Wawro after Showalter and Howard if you really want in-depth information.