If you check out the link
http://pptpclient.sourceforge.net you can get a kernel module which you can use for your kernel without re-compiling.
I have a similar scenario and I've managed to make the tunnel work.
I have a problem however, with the setting up of routes and IP addresses for the clients that connect to the server.
I have MY server connected to the internet directly and I want clients to connect to it, then be able to access resources on my LAN behind the server.
What addresses should I give the clients? do I give them addresses from my LAN and give the server end of the tunnel an IP from the LAN as well? I really am not sure how to proceed here. Any help will be appreciated. Thanks.