Installing Guest Additions
Guest Additions consist of device drivers and system applications that optimize the guest operating system for better performance and usability. Although they could be installed on the appliance earlier in this procedure, and thus propagated to your clones, an upgrade of VirtualBox (say from 3.1.2 to 3.1.4) will prompt you to reinstall the Guest Additions anyway. The most immediately noticeable feature of the Guest Additions is that the VM Window "captures" your mouse cursor, and doesn't allow it to move outside the VM window without using the host escape key combination "Right Ctrl". This is annoying, and Guest Additions is well worth installing for this reason alone, although I'm sure there are plenty of performance and usability enhancements.
Guest Additions comes with the download by default and is easily installed. Once the VM is booted, simply click on the "Devices" menu at the top of the VM window, and select "Install Guest Additions". It will go through a series of dialogs, and install in a couple of minutes. It does require a reboot.
Licensing and Activation
This article by no means offers any advice of circumvention to any of the End User License Agreements you may have entered into. You should consult your EULA for any Microsoft, National Instruments, or VirtualBox software you may have agreed to using. As for Windows Activation. If you activate several VMs on the same hardware that your key belongs to, all should be fine. If, however, you attempt to install on another platform, you will likely face activation issues. This is also true if you attempt to move an already activated appliance from one hardware platform to another. If you do not fully understand how Windows Product Activation works, you should consult this article and this article.
Although VirtualBox has worked fairly well in our test of USB and Serial devices, PCI cards such as National Instruments DAQ cards do not work. Apparently this feature has been discussed on the VirtualBox site generically for all PCI cards, not just NI. You can however create a simulated DAQ device in Measurement and Automation Explorer that will be recognized in LabVIEW on the VM. This is a potential work around.
For USB devices, you will likely want to experiment with the USB device filters in the right pane. In this screenshot, I've specifically filtered 3 devices to the XP-LabVIEW 2009 VM.