Howtoforge posted tutorial about setting Up an OpenVPN Server with authentication against OpenLDAP on Ubuntu 10.04 LTS

OpenVPN, or Open Virtual Private Network, is a tool for creating networking "tunnels" between and among groups of computers that are not on the same local network. This is useful if you have services on a local network and need to access them remotely but don't want these services to be publicly accessible. By integrating with OpenSSL, OpenVPN can encrypt all VPN traffic to provide a secure connection between machines. The OpenLDAP backend of iRedmail allows you to integrate all kinds of applications and to realize centralized account management. This tutorial shows you how to integrate OpenVPN into the iredmail ldap backend on Ubuntu 10.04; passwords will be stored in ldap and you can change passwords through webmail.

  Setting Up An OpenVPN Server With Authentication Against OpenLDAP On Ubuntu 10.04 LTS