I looked into the Virtual Machine and XP on Windows 7. Tried to download them several times on a fast connection. Never got thru the long download, and the more I read about it I decided I don't want it on my machine.
Moreover, it's absolutely HUGE and is a HUGE pain-in-the butt. I think Microsoft assumes that everyone is on a
power machine with 16gb RAM and a direct fiber-optic connection to the
Internet :-)
I've found that most 32-bit stuff I have runs fine on Windows 7 64-bit. Only stuff I have which wouldn't is old DOS programs. But, I installed DOSBOX (free) and those old BASIC and other DOS programs run just fine.
So, my advice would be to buy the updated version of Offshore Navigator and not bother with VM/XP for Windows 7 unless you really need it.
Bill