In case VirtualBox does not recognize your USB devices on a *nix system you can solve this by adding your username to the vboxusers group. Do this by executing the command:
# replace username with your, gues what, username
sudo usermod -G vboxusers -a username
Logoff and logon, start virtualbox and you should be able to access your USB devices. To access an USB device on a guest be sure to add it to the “USB Device Filters” (right click guest; choose Settings -> USB tab).
Also be sure to install the right extension pack for your virtualbox installation.