While looking for an easy way to keep my Slackware install up to date, I just ran across this article:
http://www.linux.com/article.pl?sid=06/10/12/1337224
Now that Slackware 11.0 is out, you may wonder what is the best way to update the distribution. Swaret is an open source project that aims to keep various versions of Slackware up-to-date. I use Swaret and some cron scripts to keep my servers current automatically.