1) To use knetworkmanager as anyone other than root
(via kdesu) you must create a 'network' group and add your
user to it.

2) Remove your configuration from rc.inet1.conf, or comment
out the call to rc.inet1

3) Example stuff in rc.local:
echo "Starting network-manager fu..."
/etc/rc.d/rc.dhcdbd start
/etc/rc.d/rc.networkmanager start
/etc/rc.d/rc.networkmanager-dispatcher start

4) You of course already need dbus and hal working, and
pptp/openvpn + lzo to use appropriate VPN types.

5) Sorry about the weird mix of SVN and releases here, there's
a whole load of incompatabilities, and this is the only combination
I could get to work with knetworkmanager.

6) For Slackware users who don't habitually read the Slamd64 ChangeLog
and want to use these build scripts ;) - pkghelpers is a true noarch
package, even though it's called "noarch_slamd64", it should work fine
on Slackware. It's a dependency of my ".PHBuild" build scripts that eases
portability.