Just a small tip for anyone having issues getting them detected by cgminer, I had to use version 3.1.1 and specify many -S /dev/ttyUSB0 arguments. I've got 4 mining away while I'm at work, will get all of them running at home tonight!
How do you specify those arguments? Can you post your commands? With x'ed out user/pass of course.
From what I understand 3.1.1 is cgminer --icarus-options 115200:1:1 --icarus-timing 3.0=100 -S /dev/ttyUSB0 -S /dev/ttyUSB1 ... for Linux and cgminer-nogpu --icarus-options 115200:1:1 --icarus-timing 3.0=100 -S \\.\COM1 -S \\.\COM2 ... for Windows. But you need to install drivers first in win and do some compiling in linux...