This is a case that began a while ago, but it is interesting. The issue was whether the FCC provided adequate explanation, or acted arbitrarily and capriciously, in changing its policy to permit isolated uses of expletives on broadcast television to be considered indecent under federal laws.

Prior to the case, FCC vs Fox Television stations, the Supreme Court had ruled that the Constitution allowed the government to prohibit the broadcast of vulgar words that were indecent, though maybe not obscene. The FCC previously only acted against broadcasters if they used vulgar language repeatedly or for a sustained period of time.

But after it got complaints when Cher used the F word and Nicole Riche use variations of the F word during the 2003 and 2003 Billboard Music Awards, the FCC issued an order stressing the ban on single usage violations. Fox and several other news outlets challenged the order, and my limited understanding of case law says that the Supreme Court ruled in favor of the FCC in April of this year.

At any rate, the case is interesting and is a good discussion related to Indecency and the First Amendment.
http://articles.latimes.com/2008/mar/02/nation/na-expletive2