Some Webcasters were given a stay of execution in late June, when the Librarian of Congress announced that they would be required to pay royalties at half the rate proposed by an arbitration panel last winter.The new rate, announced June 19 by James H. Billington, will be .07¢ per song per listener, and will apply to pure Webcasters as well as over-the-air radio stations that put their programming on the Internet. Royalties will be retroactive, levied from October 1998 until the end of 2002. A new, and still undetermined, rate will be instituted by New Year's Day, 2003. The US…