My GF is taking a course in Russian, I just ordered a Russian keyboard (USB). Does anyone know if its possible to use both keyboards (integrated laptop + Russian layout USB ) simultaneously ? So that pressing keys on the USB keyboard would produce the correct Cyrillic characters, and the integrated keyboard works as normal ?

A solution under either windows or Ubuntu would be fantastic!

They layout depends of the software, not of the physical keyboard. Different printed characters on top of the keyboard are the only difference between "russian" and "latin" keyboards.

I guess it's possible to use both keyboards at the same time, but they will output same characters (which will depend on used keyboard layout). Maybe it's possible to make somekind of hack in Linux, which determines by USB-id or some other means the used keyboard and changes keyboard layout automatically.

well the idea was avoiding to have to switch in software between layouts when swapping keyboards, but the russian keyboard actually has both qwerty and Cyrillic printed on it, so its ok, a software switch is good enough then, since she can stick to one keyboard.

Add the russian language and the language toolbar in windows. Then just change the language when needed. I'm not aware of any other way.