Independent network printing

We are beginning a study to convert all network printing to one basic system which will allow auditing. We currently have some printing on Novell, some on Windows domains, some on AIX, some on DB2. Our management is looking for a solution where no matter which network client you are running, you will be able to print to a networked computer. Obviously, a tcp/ip solution is the answer. Printing direct tcp/ip is out, due to the lack of auditing and queueing abilities. What are the possibilities out there today? Thanks, Mari