As trivial as its configuration actually is, I find it surprising there is no easy (as in GUI-driven) way to connect your (K)Ubuntu/Debian box to existing Cups infrastructures. Even in (K)Ubuntu 8.10 you need to use Konsole or Terminal. But then it is easy.
Easy but poorly documented.
Assuming you have a working cups server cupsserver.localdomain somewhere on the network you’re currently in; the cups config is working, i.e. printers are connected and shared and browseable.
Edit or create (this file is not in any package, so it is perfectly normal to have to create it yourself) /etc/cups/client.conf:
# sudo gedit /etc/cups/client.conf
Save the file and you’re done. There is no need to re-login, it might take a while though and I’ve found applications like Firefox sometimes do need a restart to re-poll their printer settings.
When you’re moving from net to net a lot like I am it might be easier to keep a number of files or multiple servers in the same file, uncommenting the current one when needed; that’s a matter of preference.
This works on most Ubuntu and/or Debian versions, as long as they use cups ofcourse.