Its definitely been a busy month for Google Apps with the launch of presentations (finally). As a result, there is a new video as well as an updated tour. There is no API available yet but as soon as it comes out I'll post a HOWTO.
Spreadsheets added new ways to pull external data. The external sources can include XML, a URL, HTML, or any feed based file. Spreadsheets also added autofill (type Dec and it can autofill December. Type Jan, Feb, Mar, and it will fill in the rest of the months for you. This also works with days of the week, time, and more)
The Reporting API was release into Google Apps Premier, Education, and Partner editions. This allows users to see detailed reports on how people in their organization are using Google Apps. They can track account activity, disk space, email client usage, and more.