New features include:
iCal Server 2 -- This upgrade to Leopard's iCal Server now provides push notification, wireless accessibility to your calendar from any iPhone, a new web-based calendaring interface, and updates to CalDAV that now allow you to invite colleagues to meetings via email.
Podcast Producer 2 -- Podcast Producer, which was added to the server mix in Leopard, is now improved with Podcast Composer. This new feature lets you create your own workflows for automating completion and publishing of podcasts. There's also a new Setup Assistant in Server Admin that can set up Podcast Producer 2 in a manner of minutes, even if you're setting up a cluster of servers.
Wiki Server 2 -- Workgroups wishing to collaborate now have a little bit more to love from Wiki Server. The only real new feature is iPhone support; users can securely log into confidential wikis and content, and even review content and comments from the iPhone.
Mobile Access Server -- The piece that I'm probably the most excited about as an Xserve admin is Mobile Access Server. This new feature is like a custom VPN for Mac and iPhone users. As long as they're set up in the server's directory service, users can get secure, encrypted access to the server and network with very little hassle.
Mail Server -- The engine running Mail Server has been totally redesigned for much faster service, and now provides push email, vacation messages and server-side rules, and improvements to mail server clustering.
Web Server -- The biggest change to Web Server is that it can now do HTTP live video streaming. Performance is about 1.3x faster than Leopard Server's web services as well.
Client Management -- Organizations that are deploying many iPhones will love the new client management piece of Snow Leopard Server. It has an iPhone configuration utility for creating profiles that can be emailed to corporate users, thus setting up secure services in a few seconds. Administrators can now also use NetRestore to rebuild Macs over networks, based on either a custom build disk image or a standard OS X install disk.
Best of all, Snow Leopard Server will cost $499 for unlimited users (a sharp reduction from Leopard Server's price of $999 unlimited, $499 for 10 users) and should be shipping at the same time OS X 10.6 is available to the rest of us. I'd just be happy if Apple has finally fixed a lot of the issues with backing up network users to Mac OS X Server using Time Machine.