libusb-win32 is a port of the USB library libusb-0.1 (http://sf.net/projects/libusb/) to 32/64bit Windows (2k, XP, 2003, Vista, Win7, 2008; 98SE/ME for v0.1.12.2). The library allows user space applications to access many USB device on Windows.
Poor quality assurance: The Device Driver sometimes crashes my system (Vista Ultimate 32bit with all updates), I can't even update it to the latest version and the Filter Driver stops almost all of my USB devices. Update: After spending two days with countless reinstallations, I finally managed to install the Filter Driver successfully. I hope it's stable now.
Ok, it's not really a bad project, but this should serve as a warning that it could crash or kill usb in Vista and Win7 machines just by installing - see the forum for more details. If you don't install the filter driver (or run in compatibility mode for win2k when installing), you might be able to avoid these issues.