Welcome back from "the darkside"
You can see the changes on the
Slackware homepage.
Pat lists the differences when he announces the new releases.
To determine your version of Slack issue
mingdao@james:~$ cat /etc/slackware-version
Slackware 10.0.0
and to determine you're current kernel issue
mingdao@james:~$ uname -r
2.6.7