iPhone support and push notifications
The iPhone gets some special attention in Snow Leopard Server in a few different ways. First and foremost, Apple's updated mail engine and iCal Server 2 now can send push notifications of new events or messages to iPhone users.
This is a pretty major step that Apple really needed to take. It allows the iPhone to be supported by Apple's own server platform and still maintain a lot of the features that previously would have required an Exchange Server.
Apple has also crafted a wiki template specifically for iPhone users. The "My Page" feature, as Apple has dubbed it, is formatted for easy viewing on the iPhone's mobile browser and lets users easily track additions of content specific to their job roles. iPhone users can also edit content.
Secure remote access without VPN
Moving away from collaborative tools, Snow Leopard Server introduces an alternative to VPNs for users who need to access internal resources securely from outside a network. Mobile Access Server, which makes its debut in Snow Leopard Server, allows you to create secure connections using a reverse SSL proxy. This allows users on unsecured networks like a public Wi-Fi hotspot or a mobile carrier's cell network to connect securely and to access several common internal services like Web-based intranets and wiki/blog sites as well as e-mail and other collaborative tools.
While these can be secured with SSL individually, having a single point of connection, and having single sign-on easily available and hosted by a server other than the servers storing the data, make the process both simpler and more secure. It also alleviates setting up VPN access -- which is, of course, still available -- especially if users need access to a limited number of services.
Users can now send push notications of new events to iPhones.
For remote users, you may still want to consider a VPN for access to a broader range of services.
Built-in NetRestore option for mass deployment
Apple has bundled the ability to do Apple Software Restore (ASR) deployments in System Image Utility. This is in addition to the existing NetBoot and NetInstall options. ASR deployments are typically preferable to NetBoot/NetInstall because they offer the option of using multicast system image deployment.
Multicast deployment allows a server to flood a network segment with a constant stream of data that all clients can access simultaneously -- as opposed to discrete one-to-one connections known as unicast. Multicast deployments can be significantly faster than unicast deployments through Apple's existing options.
Although this feature still requires you to rely on the ASR command-line tool for some operations, the NetRestore option allows you to easily boot a machine over the network -- removing the need for an alternate startup disk -- and proceed with the deployment.