Something very interesting...

Google has released a set of Atom APIs called "GData". First one is for the new calendar. Hopefully this means we'll start seeing ways to embed various calendars into other webpages and applications.

The Google data APIs ("GData" for short) provide a simple standard protocol for reading and writing data on the web. GData combines common XML-based syndication formats (Atom and RSS) with a feed-publishing system based on the Atom publishing protocol, plus some extensions for handling queries.
http://code.google.com/apis/gdata/overview.html