Tungle.me - Eliminate back and forth of deciding when to meet

http://www.tungle.me/Home/

This is a service that allows you to eliminate the back and forth of scheduling between people.

From there site –

Scheduling Made Easy

Tungle.me is a scheduling application that syncs with your existing calendar.
Eliminate double-bookings, time zone mishaps and the back-and-forth of finding a time to meet
Easily schedule meetings, inside or outside your organization
Invite others to schedule with you, without having to sign up