Thanks for the reply.
It doesn't actually solve my problem, but has given me a few ideas.
As I understand it, I can't boot a PC ( ie Wake On Lan) and view the
Grub boot selection screen remotely, which is what I want to do.
Perhaps I can either use KDM/GDM on my main PC to gain remote access (
that is an option), but still think that I could only access an already
booted OS, as to gain access via TightVNC, the OS has to have booted and
loaded in order for it to start the TightVNC Server.
Perhaps I can set up KDM/GDM with XP as an option and have it run a
script to reboot into XP?
At present, pending any other solution, I think I'll just use a
removable hard drive caddy to allow me to attach the drive/os from which
I want to boot.