If you are trying to coordinate dates with another person, Google Calendar can be a great way to go about it. It is simple to use, and you can set it so that another person can add their events to the same calendar. A synch with Microsoft Outlook is offered as well for those of you who prefer to use that, but you can get everything on one document easily here.  Joe and I are currently using it to map out all of our travel dates and speaking engagements for summer and spring, so that we have a master document to reflect what is going on.