libftdi - A library (using libusb) to talk to FTDI's FT2232C,
FT232BM and FT245BM type chips including the popular bitbang mode.

Note: When you get a -5 error "can't claim usb device" during
ftdi_usb_open(), make sure the kernel ftdi_sio driver is unloaded.

WWW: http://www.intra2net.com/de/produkte/opensource/ftdi/