College Board AP Central
Why not just go straight to the source? The College Board actually has quite a few informative resources ranging from scoring guides to tips and practice.
Funnel Brain
Here's a bunch of user made flashcards. Given that they are not "official" the quality may vary. However, there is a decent selection to choose from -- just make sure to do a little fact checking.
AP Pass
This is a calculator to figure out your AP score. It's a pretty neat way to visualize how exam scoring is done.
Bench Prep
This blog is orientated for long term preparation, so it may be a bit late at this point. Regardless, there are a few useful things that can be gleaned from it still.
AP Study Notes
This website has a massive collection of examples and study topics. It's hard to do better than this if you're going for the classic "study 'til you drop" method.