How Do I Install VPN for Connecting IP Phones?

uh, your talking about two different things where I come from. VPN for phones is built into the service. If you want to get Vonage, give me your email address so we can split some free months to recommend you. Whereever you take the router and connect to a high speed connection, you can make calls with the same number anywhere in the world on the internet. There's free ip phones if you have yahoo, aol, they just work over the messenger services (and you can cam too) or use http://www.skype.com/download.

Now, VPN itself can be open source free or expensive, but it would be to extend your network, not for IP phones. Check out http://openvpn.net.