OpenNETCF used to have a product that provided RAS capabilities. Well Microsoft deprecated RAS in WindowsMobile - starting with WinMo 5.0 as near as I can figure - in favor of Connection Manager. That depracation actually broke RAS in some scenarios. FOr example, if you create a RAS connection and then try to use a managed TcpClient, it will try to create it's own connection through the Connection Manager instead of using the connection you created through RAS.
What this did was skyrocket our support incidents for something that we sold very, very few licenses for. In the interest of keeping our sanity, yet allowing people using plain of Windows CE to still use RAS, we made the decision to just make it a shared source project. It's now out on CodePlex. If you need support for it, we still offer consulting services, but everything is there to get you going.