I learned about internet printer protocol and with a bit of
research, I found that I could define an ipp printer to Windows Vista.
Now, my Windows Vista Virtualbox guest of my Ubuntu host can print to a
laser printer connected to a different Ubuntu PC on my home network.
Thanks for offering help.

If anyone out there is looking to do the same thing, they should check:

howto.ccs.neu.edu/.../adding-an-ipp-printer-queue-to-windows-v\
ista/