Amontec JTAGkey
From Openmoko
The Amontec JTAGkey is a USB to JTAG adaptor sold by the swiss company Amontec (http://www.amontec.com/). They also offer a very inexpensive variant called JTAGkey Tiny, which is more or less the same hardware, but without level shifters. This menas that low-voltage signals might not be picked up.
However, on the Neo1973 Hardware, the JTAG voltage is 3.3Volts, so no level shifter is required, and the JTAGkey Tiny can be used.
Please note that since we now have our official Debug Board we obviously encourage using this