Google improved Google Calendar scheduling inside Gmail:
A new repeating event editor
The old interface for creating recurring events was clumsy and took up too much space on the screen. Now you'll see only a summary of your recurring event on the main event page; if you want to edit it, you can use a window that opens when you select the "Repeats" checkbox.
A new tool to help you find a time for your event
You'll notice a new tab on the event page that should make it easier to find a good time to schedule an event. When your friends or coworkers give you permission to see their calendars, you can click this tab to see a preview of their schedules and hover over their events to see what conflicts they might have. This should make scheduling a tad easier, especially for events with large numbers of guests. For Google Apps users, the new schedule preview can also show data from other calendar services using our Google Calendar Connectors API.