Not quite sure i understand the problem from the info so far.

a] what exactly do you mean in the first sentence "ubuntu 8.10
printer". You have a printer that'll work on ubu 8.10 and want it to
work on win2k? In ubu when it is installed [assuming printer is
connected and switched on] it will setup the printer automatically
finding correct drivers. So why do you want to set up a printer for a
lower grade OS like windoze when ubu does it perfectly!

b] you have two XP machines and you added the printer drivers from a
disk or downloaded them. Works ok? good

c] laptop win2k older software so doesn't have drivers already
installed. Go to manufacturers website and they'll probably have the
driver there for download - win2k version. I'd be surprised if the
drivers were different from win2k and xp. Some are - some aren't. I
have a scanner that works on one driver file for win98 to xp.

The printer is installed on the Ubuntu 8.10
machine and works ok. I have 2 XP machines using this printer over the
network. The problem is I can't do this with the Windows 2000 machine.
I installed the printer driver directly to the 2000 machine along with
the drivers and it printed ok but I want to print from this pc over the
network. Maybe it is because it's windows 2000 and I'll have to talk my
son into upgrading it, maybe to Ubuntu

Seems it is a problem with win2k [NT] talking to network? Putting ubu
on the laptop would give you a faster machine

I have had the same issue trying to print from my Vista to Ubu 8.10
system printer too. I will have to try entering the direct system
address like you show once I find out what IP address it is.

I just started out in Ubuntu and
have been asking lots of questions :-) I hope I can give you a good
answer. I haven't done too much work with Vista but printer sharing
should be the same as XP. It helps if the Ubuntu machine has a
permanent IP address. I made mine 192.168.1.5. In printer
configuration under server check the settings you want. I selected Show
printers shared by other systems, Publish shared printers and Allow
users to cancel any job. Under the printer properties check shared.

On your windows machine I had to install the printer to load the drivers
because it wouldn't show my model. Just temporarily connect the printer
and using the cd that came with the printer do an install. Then connect
the printer back to the Ubuntu machine and do another add printer on the
windows machine. Check connect to a printer on the Internet or on a
home network and in the URL entry enter the direct address of the
printer including the ip address of the Ubuntu machine, the word
printers and the printer name. My example is:

http://192.168.1.5:631/printers/ml-20102

Hopefully this works on your Vista machine. If I can't get the win 2000
machine to work I may have to talk my son into installing Ubuntu. He's
not as geeky as I am so he may not go along with it

Thanks I will try this out, I may have to see how to set the IP as
static, then I can maybe move ahead. Once I get to where we can print
from our laptops through the desktop then I will leave the Ubuntu
on it, as it is now I have XP on the desktop to allow remote printing.
I have a tray in the desktop which allows me to shutdown and remove the
disk, and reboot on the other system. About 10 minutes at most.

That's what I was doing it also, keeping a Windows XP machine running
just to act as a printer server. Now I use the Ubuntu machine for just
about everything. You can change your network setting by right clicking
the network icon on the top of your desktop and selecting edit. Under
IPv4 Settings you can select manual under method and then add then enter
your address, netmask and gateway. Here's a good document on the CUPS
printing.

https://help.ubuntu.com/community/NetworkPrintingFromWinXP

This is definitely not a textbook approach, but it might work:

* On one of your XP computers, define the printer as shared
* On the Win2k box link to that printer..

Win2k is probably missing something to connect to non Win environments.

Man that sounded like it would work, but when I went to the XP machine
and clicked the printer properties and then click Sharing it said
Sharing is not supported for this type of printer. I guess when it is a
shared printer and your accessing it with a URL with CUPS it doesn't
like trying to share it another way.