Not sure why this is giving you so much trouble but I believe the MP600R will work fine on Snow Leopard once we get the machine correctly configured. I think I made an assumption that you were printing fine via wireless with another version of Mac OS X. But given that the printer does not appear to have/had an IP address set, then it would suggest that you were not printing previously via wireless. Is this correct?
To configure the IP address in the MP600R you have to connect the printer to the Mac via USB. Then you select the USB attached MP600R in the Printers list and open the Options & Supplies > Printer Utility. This will open the Canon IJ Printer Utility. Here you select the MP600R and now the Network Settings button should appear. If the button is still not present then you may have to download and install the
Canon IJ Network Utility v2.70. In testing 10.6, my printers have already been configured for the network so I have never needed to do this setup step and therefore I am not certain if the facility exists to configure the network settings without this tool being installed. Apologies if this has been the stumbling block.
Once you have the Network Settings button present, select it and go through the procedures to configure the network settings. Once this process has completed, the setup will prompt you to turn off the MP600R and then disconnect the USB cable. Then when you power the MP600R back on, the machine should be connected to your wireless access point. At this stage you can check that the MP600R has an IP address via the Device Settings menu on the printer (refer back to my third reply to check how this is done).
Once the printer has an IP address and shows that it is active, you can now add another printer queue, this time for the wireless connected MP600R. Open Print & Fax, select to Add ➕ and choose the Default view. As I said in the first reply, you will probably see the MP600R immediately as a Bonjour Scanner, but we need to wait until the MP600R appears with its Kind column showing 'canonijnetwork'. When this does appear, select it and the Print Using menu will automatically find the correct driver. Click Add to finish adding the network printer queue.
Hope this stops the hair reduction....
Pahu