Are these the Xilinx development boards?
What you need to do is load the sha-256 FPGA logic (in a format like VHDL) onto your FPGA chips. Without the bitcoin hashing code, all an fpga is is a bunch of logic gates that have no state.
http://www.taylorkillian.com/2013/04/using-fpga-of-eecolor-color3.html - gives a pretty good overview of loading the open source fpga miner code onto a random fpga board using a jtag cable. It also links to the github project you will need.
In all honesty, if you are just interested in doing a little bit of mining, you will get more speed with a lot less headaches by just getting 4 or 5 USB Block Eruptors off of Ebay, and a 20 dollar or so hub. FPGA's are tricky business, and you really don't get the speed from them.. Electricity is not so much a concern, but you should actively cool them depending on how high you clock them.
Good luck.
