I was looking into getting an vpn connection from my iphone to my server because I wouldn't want to send my email passwords and webpasswords clear over any public WIFI. Setting up an open source vpn connection from the Iphone is fairly simple but there is not much choiche of software. To my knowledge OpenVPN and Openswan are not supported so my choiche came down to: Poptop which is probably not the most secure solution because it's uses the Microsoft protocol which has a few flaws but I figured it would be much safer then nothing and if there is an evil WIFI I would guess they will just go for the easy targets.
My install is a CentOS 5.2 installation but it should work under any fairly recent Linux distribution
Setting Poptop VPN for Iphone is done in just four steps: