The British Library says it's creating an archive of the country's defunct Web sites to preserve snapshots of the ever-changing internet for posterity. The library is already charged with keeping a copy of every published work distributed in Britain and Ireland. In 2003 that remit was extended to electronic materials such as compact discs and online publications. Now the British Library says it's begun trawling through the Web and making archival copies of sites of historic interest -- including those once maintained by now-bankrupt companies such as Woolworths, Web pages spawned after the July 7, 2005 terrorist attacks in London and Internet coverage of Britain's last general election. The Library said Thursday it had so far archived 6,000 sites. 