I was having trouble getting my 'unsupported' networked Canon ip1600 to work over the network (so I could print wirelessly from the Mac to my Windows PC without a print server). Canon was no help -- they told me what I was doing was impossible and unsupported. No matter what I did, I kept getting NT_STATUS_NO_MEMORY errors, or login errors. So I searched around the internet and found a ton of tips, and the following combination seems to work every time for me:
smb://guest@workgroup/servername/printerMac OS X Hints
http://hints.macworld.com/article.php?story=20060704025823635