OCS 2007 presence schema and XSD available

When I talk about UCMA in the UC development classes I've been teaching, attendees frequently ask how they can publish custom presence information. The answer is that you can construct custom presence in two ways: using your own completely custom schema (which CWA, OCS, and other MS applications won't understand) or by passing presence data using Microsoft's presence schema. That schema is documented here, which makes it much easier to take the second route.