Apple will discontinue its Xserve rack-mount server in January. Why? “Since its introduction in the fall of 2009, Mac mini with Snow Leopard Server has become Apple’s most popular server system,” the company says.

Apple will continue to sell its rack-mount server product through Jan. 31, 2011, and will continue to honor warranties and support contracts. Apple has posted a Xserve Transition Guide (http://images.apple.com/xserve/pdf/L422277A_Xserve_Guide.pdf).

Every Xserve ships with an unlimited client edition of Leopard Server, offering support for Mac, Linux and Windows clients without the added cost of client-access licenses. Leopard Server sports Server Assistant and Server Preferences, which allow even nontechnical users to quickly manage users and groups on the server and easily set up key services, according to David Moody, Apple’s vice president of Worldwide Mac Product Marketing.

Leopard Server includes Podcast Producer, a way to automatically publish podcasts to iTunes or the web; Wiki Server, allowing people to collaboratively create and modify their shared web sites with a few clicks; and iCal Server, a commercial CalDAV standard-based calendar server. Leopard Server is fully UNIX compliant and LDAP and Active Directory support allows Xserve to fit right in to existing IT environments.