REPOST: A simple way of distributing a VPN client installation is to create one with CMAK (Found on your WIndows 2003 CD), even though this is mostly aimed at Microsofts ISA server VPN it should work fine with other providers (supports L2TP and PPTP). Its fairly easy to get started and you end up with a single .exe file you can distribute to your users.
One minor glitch seem to be in regard to DNS, you may need to configure a script to deal with this (to ensure that the PPP adapter is the first in the search path. There is a lot more on this in the links below.
Anyway, here is a few links to get you started;
http://blog.msfirewall.org.uk/2008/06/using-cmak-to-configure-isa-server-vpn.html
http://blog.msfirewall.org.uk/2008/06/using-cmak-to-configure-isa-server-vpn_10.html
http://www.carbonwind.net/ISA/VPNQ2006/vpnq2006_4.htm
https://207.46.19.190/windows/windows2000/en/advanced/help/cmak_ops_65.htm
http://www.isaserver.org/img/upl/vpnkitbeta2/cmak.htm