BusyCal is like iCal Pro, and it's now in public beta
BusyCal is a calendar app for OS X, and its developers would like you to think of it as "iCal Pro." It's designed for families and small groups, and includes a handful of syncing features that make collaborating on a calendar a lot easier. BusyCal syncs to Google Calendar, and it syncs to multiple machines over a Bonjour network, which is ideal for a multi-user home or an office.
Design-wise, it's like iCal with a lot of nice usability improvements. It's close enough in terms of layout and features that iCal users shouldn't have any trouble switching, and it imports your iCal calendars automatically when you start it up for the first time. Among many, many other features, BusyCal also does iPhone syncing, multi-user editing, and a customizable list view. If you're already an iCal or Google Calendar user, it's well worth giving BusyCal a shot.
Design-wise, it's like iCal with a lot of nice usability improvements. It's close enough in terms of layout and features that iCal users shouldn't have any trouble switching, and it imports your iCal calendars automatically when you start it up for the first time. Among many, many other features, BusyCal also does iPhone syncing, multi-user editing, and a customizable list view. If you're already an iCal or Google Calendar user, it's well worth giving BusyCal a shot.

