AP Resources

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.