Google's much anticipated calendar program is now available (although still in Beta). As you might expect, Google Calendar is free, fast, and well integrated into their Gmail software. The ability to create and share multiple calendars makes this a possible solution for scheduling project milestones with clients.

Think of your biggest client. You probably have more than one project you're managing for this client. With a Google Calendar you and your client have a single place where every project meeting, milestone, and deadline is scheduled. Use this tool for all of your clients and you now have a specific calendar for each client.

In addition to having a unique calendar for each client, you can overlay all calendars into one master calendar (or just show a few calendars together). Your master calendar can have layers like a Photoshop file and you can switch individual client calendars on and off at will.

With Google Calendar's sharing capabilities you can control who sees each calendar (invite them via email) and how much control they have over the calendar. Want someone to only have "view" access? No problem.

Google also makes it easy to disseminate calendar info by supporting RSS (new events are automatically "sent" to subscribers) and iCAL (a standard file format for sharing calendar info between programs).

View a tour of Google Calendar