Gizmo Project makes all VoIP to landline calls free. Forever. - Engadget

Gizmo Project makes all VoIP to landline calls free. Forever.

You must have Gizmo Project to make the calls, and the person you are calling must have it too. They must fill in their landline number in their profile for you to call that number for free. You also both have to be 'active' users, i.e. you can't setup an account for someone, login once, configure their profile and then call them for free forever.

Still beats Skype's 'US-only, this year' offer.