Tunnelling traffic through my server using an application

Question

I own a small but fast growing VPN service that has about 60 clients. After a lot of demand, I am looking to build an application that my clients can use to connect to our VPN using a custom client. I would normally pay out for a professional to do this, but our cashflow does not currently allow for it. Something along the lines of this:

http://hidemyass.com/vpn/

I'm just stuck now at how I would go about tunnelling all of the clients traffic (not just their traffic through web browser) though my server using a client I am going to build.

I'm thinking along the lines of changing the Windows network settings like you would have to without a client, but doing it programmatically.

Any input would be helpful, thank you. :)

Answer 1

Look at openvpn, which is designed to do exactly this. You can push routing information to each client as it connects to your server.

Answer 2

Run a linux server and any number of free VPN servers? A quick google came up with http://www.natecarlson.com/linux/linux-vpn.php or http://articles.techrepublic.com.com/5100-10878%5F11-6038003.html or http://www.poptop.org/