The first bit is easy. Look for a tool on the Microsoft web site called
Print Migrator, or PrintMig. Bear in mind that it doesn't migrate any third
party port monitors you may have. You'll need to manually one of each type,
if you have any, prior to importing on the target server.
For the second part of your question, you can script with WMI, or you can
use variations on the "rundll32.exe printui.dll,PrintUIEntry /in /n
\\printserver\printer" command
http://www.google.com/search?hl=en&ie=UTF-8&q=rundll32+printuientry
Removing the old printers can be achieved using a similar command, but I
can't think of a way of retaining users' default printers.
If you don't like my answer, I'd recommend reposting to
microsoft.public.win2000.cmdprompt.admin, or
microsoft.public.windowsserver.scripting. There are some awesome scripting
guys who hang out there.
Talking of scripting, a trip to the TechNet Script Center may be worth your
while, too.
http://www.microsoft.com/technet/community/scriptcenter/default.mspx
Hope this helps
Oli