NPR's Larry Abramson reports on the censorship battle over the use of filtering software on Internet-linked computers at public libraries. Most libraries now have an Internet connection and some use filters to block pornography and other offensive material from the computers. A federal court ruled recently that the filters used by a library in suburban Virginia violated the First Amendment. (7:31) THIS IS THE FIRST OF TWO REPORTS. TOMORROW LARRY ABRAMSON WILL REPORT ON THE LEGAL AND TECHNOLOGICAL LIMITS OF SOFTWARE FILTERS.