Slashdot's got a quick & dirty preview of the new OS X "Tiger" server.

"It also adds a Jabber server that provides the option of serving iChat. SSL/TLS and Kerberos can be added for security. A single Tiger iChat client can have chats running on multiple servers, so a user can be on the main iChat server, while having private chats on a company server. Because it is Jabber, non-iChat (and non-AIM) clients can participate too."