I contacted Mr. Summers again to obtain some clarification:

Mr. Summer, I appreciate your detailed and honest response. I am also very glad that you recognize just how out of line Mr. Beck has been lately. Yet I must question how committed you are to dropping support for Mr. Beck's rhetoric: today, Binder & Binder ran two adds on the Glenn Beck program. Now, I understand that you use the Run of Schedule format for your advertisements; I also understand, from your previous email, that you have instructed Fox News to pull your ads from Beck's program. Has Binder & Binder reversed its position regarding its advertisements? Or has Fox News simply refused to honor your request? That would seem to be highly unprofessional conduct. Thank you for your help in clarifying this matter

This is the response I received:

Under our present contract, I simply can't control where Fox news puts the Binder and Binder commercials.

So, Binder and Binder has asked Fox to remove its ads from Glenn Beck; Fox has simply refused to honor that request.

This refusal is telling. Fox can no longer depend on a large stable of wealthy advertisers to fill in should a RoS advertiser ask to opt out of a specific program. Despite frequent calls of irrelevance by Fox and other media organizations, the movement against Glenn Beck is working. Fox has become defensive, struggling to retain even the small RoS advertisers left. It cannot sustain this steady loss of advertisers, especially if those advertiser start dropping Fox entirely (as Binder & Binder has threatened to do if Fox doesn't honor its requests).

The message is clear: Keep It Up.

UPDATE:

I want to thank you all for the rec's. Also, upon reading many of your comments and scrutinizing Mr. Summer's replies, I've come to the conclusion that he did indeed structure his words with some wiggle room built in. I've contacted him again asking for clear responses. However, I don't doubt Mr. Summer's personal opinion on the matter - he more or less called Beck's comments the rantings of a drunk - just the possible profit motivations (which are always quite motivating). I'll keep you all updated.

In the mean time, keep contacting Beck's remaining sponsors - by email, by phone, or (as one commenter suggested) by snail mail. Several commenters have posted excellent sample emails; every extra voice helps.