My version CUPS is 1.2.2. I have used russian letters at the "Info" and "Location" field in printers.conf. In browser I perfectly see the russian letters at the "Info" and "Location" field of printer description. But via Samba 3.0.23c I see "raw" string as in the printers.conf at the "Info" and "Location" field of printer description.
can you please post your smb.conf and you printers.conf? Please gzip it before sending so that the encoding won't be changed.
Now I have Samba 3.3.3, CUPS 1.3.9 and UTF-8 locale. This problem is absent.