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You've gotten some excellent advice already.  I'll add a few of my thoughts. First of all, have you been doing link building?  If not, then this may not be the right road to go down.  If you've noticed a drop just recently, it may be that the Panda algorithm is affecting your site and Panda really isn't about link quality.  There was a big Panda update on May 20 although many sites started seeing changes a couple of days before that. If you have been doing link building and you want to clean up your links then the goal is to find ones that were self made with the intention of gaming Google and then remove or disavow those. William's list is a good place to start.