Can I use my USB devices with the guest operating system in QEMU?
It depends. Initial support for USB device proxy and emulation is now available in QEMU 0.8.0. From Fabrice Bellard's email to the QEMU developers list:
I just committed an initial USB support for QEMU. This USB layer will ultimately enable QEMU to use some host USB devices and to simulate USB devices. WARNING: the current USB support is for USB hackers only - it is not meant to be fully usable yet.
Please see:
http://lists.gnu.org/archive/html/qemu-devel/2005-11/msg00062.html
Flash drives have been reported to work. Things such as USB cameras will not work yet, as the USB support does not relay isochronous operations yet (but this is pending).
Experimental patches for Windows and FreeBSD host USB device support at:
http://gnome.dnsalias.net/patches/
If your guest OS is Windows, Keyspan makes a USB hub that is accessible via Ethernet. In the real world, you would use this to let your PC use a USB device that is located elsewhere in your building via Ethernet instead of running USB cables (and repeaters) down the hall. I'm just guessing here, but a Windows guest ought to see this device and its connected USB devices if you bridge your virtual LAN to your real LAN. (If you try this and it works, please post the info here!)