If you're interested in this have a look at: http://internet.newsforge.com/article.pl?sid=06/06/02/185227&from=rss It's really an introductory article for those who don't know much about this area (like me!) -- Ian McDonald Web: http://wand.net.nz/~iam4 Blog: http://imcdnzl.blogspot.com WAND Network Research Group Department of Computer Science University of Waikato New Zealand