About a year ago, Greg Wilson has started a very ambitious book project about the architecture of open source applications. The line-up was impressive, since more than 20 people have started to write about various topics. From the Battle of Wesnoth to Audacity, via Mercurial. And the project is, as of today, completed !
Everything is available online, but you should consider buying it at LuLu because all royalties are going to Amnesty International.
I can't really give a detailed review about the book yet because I am still reading it, but I already can tell you it's awesome :)
And I am proud to say that I've contributed a chapter about Python packagingin which I am trying to explain what we're doing to improve the situation. This is a good timing since I've just pushed packaging into the standard library. So if you want a bit of background in this area of Python, read up. The chapter should be pleasant to read thanks to the work of Greg Wilson and Amy Brown. They managed to convert an awful Frenglish chapter into something that is readable.
Again, you should buy a copy of that book.