The guy that runs Injustice Everywhere performs an invaluable service keeping track of all the incidents around the country where police officers are simply out of control.
If you suffer from the delusion that most cops are honest, and it's only a handful of bad apples out there, then you haven't been to this excellent website!
But I only now have noticed his victim's guide. What do you do when you've had a run in with Po Po, and they've streamrollered your rights? Go take a look at this compilation of excellent advice:
A Police Misconduct Victim's Guide
By the way... this guy's been out of work for quite some time and is facing eviction. If you can... lend a hand will ya?