There are going to be two models the first is the 1500 the second is the 1900. They both with have an Intel Celeron 4xx processor, half a gig of DDR2, 256MB of flash storage, gigabit LAN, 4xUSB (two front, two back), 2x eSATA, and then all the media, instruction booklets, and cables necessary to get things going.
From there they begin to differ, actually they differ mainly in storage capacity that comes with the server, number of drive bays, and likely weight since one has one more drive than the other. The 1500 comes with 500GB of storage in a single drive and has 3 spare drive bays.
The 1900 comes with 2x500GB drives and it says it has 3 empty drive bays as well, but since the units as a whole are both the same size, it seems that was a typo and there will likely only actually be 2 empty drive bays. Software wise you get software to manage the server, software that informs you of fan speeds and temperatures and then PacketVideo’s TwonkyMedia streaming software. All I’ve got is the UK pricing which is £399 and £469 respectively and apparently they are shipping in the next two weeks.