Cheap Tag

Cheaptag is the equivalent of a Xilinx Parallel Jtag programming cable which you can make up from bits and pieces of dead ISA cards and old wires that are lying around. It is intended to cost nothing at all, even if you bought all the parts it would be a couple of dollars.

• Powered by the Jtag device it is plugged into
• Suitable for 5V-tolerant designs only (eg, 9500, 9500XL)
• The Xilinx software accepts it as a Xilinx Parallel cable without any configuration being necessary
• Cheap, unbuffered design means it will not work with some poorly designed printer ports, but will work with 99% of the ports out there.

http://warmcat.com/milksop/cheaptag.html for more information