How to setup pptp VPN server on Linux [Tutorial]

I’m moving to Japan very soon and remembered that Google Voice won’t be working once I step onto Land of the Rising Sun. So I figured I should setup a VPN tunneling for me to access services that is available only in the US. Setting up PPTPD is fairly easy and straight forward. I’m using SoftLayer BYOC (Build Your Own Cloud) which cost $70/month for 2TB bandwidth (inbound bandwidth is free – unlike Rackspace cloud).