I am running Windows XP as a virtual machine through VirtualBox on Ubuntu 11.10. I have some USB devices (namely a video grabber & Android phone) that aren't recognised by Ubuntu. Will they be recognised by Windows XP if it is running virtually?
Probably, yes. The USB-passthrough gives native-like access to USB devices to VMs.
In the past I've used VirtualBox to update the firmware on my old phone, the firmware on my mouse (it's a very shiny mouse) and update our Logitech Harmony remote. All things that aren't really possible through Ubuntu directly.
What I should point out is that the performance is not great all the time. It isn't a real passthrough (that's practically impossible as the hubs are all managed by Ubuntu) so there's a software layer in there that does slow things up. Pointedly for you, a video grabber may not work very well.
Note: I thought this didn't need saying but, just reading Frank's answer, it probably does... All this does require you to set up USB support correctly!
