For me, setting up an OpenVPN server on Ubuntu Server was orders of magnitude easier than trying to use a commercial ipsec utility. Here's the steps to take to set up an Ubuntu 8.04 (Hardy) server.

First, be aware this setup makes a few assumptions. First, no bridging of networks is done which means no broadcast traffic and no multicast. I believe most people won't use those, so I'm not even going to try to explain how to make that work - I'm going for a quick and easy setup. Second, the server is on the Internet with a static IP address - or at least has a DNS entry somewhere so that computers on the outside can locate it. Your typical home network won't have a static IP, but with some of the "dynamic DNS" website / utilities, you can get around that restriction.

I'm also not going to try to deal with firewall issues in this HOWTO. If you can disable your firewall and everything works, then get your firewall working afterwards. The best advice I can give there is to allow all traffic to/from the "tun0" (or tun1 or tun2... whatever) device that the VPN creates, and allow incoming traffic on the Internet facing adapter (eth0?) to the TCP or UDP port you configure your server to listen on. It's really not that complicated for a basic setup.

First, become root (sudo su -) and then install the following:

apt-get install openvpn dnsmasq openssl

I've been practicing at photography for a while, and there's a few things I've learned that I think applies to most any thing you want to be good at.

1) Practice before you stick your neck out.

What do I mean? It's nice to show off photos you've taken after the fact, but if someone expects you to take pictures of THEM and get good shots, well you better be ready. Better to take 400 pictures of plants in your backyard every day for weeks so nobody knows you take 399 bad pictures for every one good one. You can always take pictures of friends later after you have improved your ratio to something better, like 200 to one. :-)

2) Every professional works from a bag of tricks that he repeats and builds on, but still has a basis in some trick he knows.