For a $600 pledge you will receive a set of gantry parts milled out of 3/4" MDO, plus design files and a bill of necessary hardware. You do not get any hardware, motors, electronics, or parts for a table. Put another way, I'll be sending you the only parts of the Kikori that cannot be easily procured elsewhere.
The approximate cost of the rest of the BoM is $1900, plus the cost of a router (I used a $300 Porter Cable 3 1/4 HP router motor) and a computer.
Yes! I use EMC2 (http://linuxcnc.org/) to control my Kikori. In terms of creating g-code files to run on the machine, I recommend this article for a list of open source programs available: http://www.mechanicaldesignforum.com/forum/kb.php?a=22