Apple today unveiled the Xserve, its highly anticipated rack-mount server that packs high-end features in a 1U enclosure. The Xserve utilizes double-data rate (DDR) SDRAM — the first Mac to do so — with support for up to 2GB and features dual Gigabit Ethernet, three PCI slots, and support for four Ultra ATA/100 hard drives, another first on the Mac. The Xserve will be available in June with Mac OS X Server in two configurations: 1GHz, 256MB RAM for US$2,999 and dual-1GHz, 512MB RAM for $3,999. The server can be configured to order at the Apple Store.