That seems to have changed a little bit going from Tiger to Leopard.
In Tiger, you gotta launch /Applications/Printer Setup Utility, single-click on printer of interest, then click on "Show Info" icon in toolbar. Select "Name & Location" from pull-down menu.
You can get to Printer Setup Utility from Sys Prefs | Print&Fax printing panel then SINGLE-click on the printer entry to select/highlight then click on Printer setup button (double-clicking on the printer entry here just launches /Users/saginaw66/Library/Printers/{printer}.app where you can get status of active and completed jobs but can't change name from there).
You might also want to pay a visit to /Users/saginaw66/Library/Printers in the Finder and rename the application, too. On mine (running 10.4.10), even though you changed the printer name in Printer Setup Utility and that change is reflected in Sys Prefs | Print&Fax and in the print dialog box of active applications, it was not updated in the actual filename in Finder.
