Thanks for the Links. I finally found a Solution wich works for me:
I use an old G4 running Mac OSX 10.4.11 with a static IP Adress.
On this machine I enable printer sharing.
On my IMac running MacOSX 10.6.4 I had first to install the additional printerdrivers package from the leopard Install CD (optional installs).
When adding a new printer in the fax&print system controlpanel (IP Printer) I entered the static IP adress of the G4 and chose
LPD (Line Printer Daemon) as the protocol. After that a printer was automatically found and the driver for a generic postscript printer applied.
To test the printer i printed a document from InDesign CS 5.
