This article was first written in June 2004 for the BeezNest technical
website (http://glasnost.beeznest.org/articles/135).
To change the default printer when using GNOME, it is pretty  easy, provided that you use CUPS and gnome-cups-manager.
Go into the "Applications" menu, then "Desktop Preferences", and "System  Tools" and click on "Printing".
There, you have a list of all preconfigured printers on the system. Right-click  on the one you want by default and click on the "Make Default" menu entry.  If this one is greyed and you cannot click on it, it means it is already  the default.
Now, any application should print on this printer by default, unless otherwise  told.