A common complaint I hear when one of my clients upgrades to a new system is how Apple abandons their old users. It's frustrating. Trust me, I understand. This was never more evident than in the transition from OS 9 to OS X. Without trying to justify Apple's reasoning, I'll offer a little support here.
OS 9 had built-in USB printer sharing. I never used it much. OS X has much better printer sharing, thanks to it's Unix underpinnings. I still don't use it much. The best solution is a network-capable printer or print server. I've been a big fan of Hewlett Packard's JetDirect product line, and they have supported Appletalk for years.
If you need to share an HP printer between OS 9 and OS X, the HP JetDirect 175X is your ticket. It supports a wide range of (HP) printers, network protocols, and operating systems. Even Windows!
Connect it to your router, switch or hub with the built-in RJ-45 ethernet connector, and it shows up on the network. Very easy. They can be found on eBay for under $100.
If you want an alternative, or are just too cheap to pony up the 100 clams, Apple offers this procedure for sharing a printer between OS 9 and OS X machines. Beware: It's a bit of a hack, and I have had mixed success with this method. In particular, access to the lpr queue from the OS 9 machine is a bit flaky in my experience. But you can take that up with Apple.