I had been putting off adding my Canon MP600R to my new iMac, as the process on my 10.5 iMac was not simple.
Well things have improved with 10.6 as it was very simple and much easier than with previous versions of OS X.
The key though was to have some patience as it can take a bit of time for the printer to appear in the printer list.
Once though it “appears” then it is quite easy to add the printer like any other USB, network or Bonjour printer.
Once added though, run Software Update to get the most up to date drivers from Apple.
Next job to be able to scan from the printer.