Cell phone owners will be allowed to <A HREF="http://www.cnn.com/2006/TECH/11/23/digital.copyright.ap/index.html">break software locks</A> on their handsets in order to use them with competing carriers under new copyright rules announced Wednesday. Other copyright exemptions approved by the Library of Congress will let film professors copy snippets from DVDs for educational compilations and let blind people use special software to read copy-protected electronic books.