The way Virtual Box works it will use the graphics card and monitors attached to your host computer. This means that the guest OS only has a virtual graphics adapter to operate.
To answer your question: Yes, it is definfitely possible to view the screen of your Virtual Box guest Windows on a monitor or beamer attached to your Ubuntu host computer provided Ubuntu is able to adress it (which is very likely the case). You don't even need any additional drivers for Windows. When running Virtual Box in full screen mode it will operate very similar (but slower) to a native Windows.
The present release of Virtual Box allows providing multiple virtual monitors, all of which can be displayed from the host OS. If we installed the Oracle Extension Pack to make it a PUEL-version we are even able to view the virtual screen over a network using the RDP protocol.