Balancing the media and "silencing" talk radio?

I know lately there has been a lot of talk about the "silencing" of talk radio and how the media is more often than not liberal (minus Fox News). I am writing a paper on it and I was wondering if there is any specific legislation/current events that relate directly to regulation of these matters other than the fairness doctrine and equal time act. Your opinions would also be greatly appreciated as well :). Thanks!