As you type, QuickCal will show you what it is thinking, as well as pointing out any schedule conflicts with events you're about to create. In addition to this, QuickCal supports "Smart Reminders", which will create alarms at configurable time intervals, specific to how far in the future the event is. A meeting tomorrow? Reminder 15 min in advance. A meeting in 6 months? Remind a few days in advance. The QuickCal menu icon also will show you all events on your calendars for the current day. Quickly see what's going on at a glance.
Mac OS X 10.6 Intel