I have an old CanoScan D646u scanner (~2003). I can't find any drivers for it on the Mac OS X (10.6.6). Is there something I can do? I'm thinking of a generic TWAIN driver, if that would work. I'm not sure where to start, though.
Give Vuescan a try. They support a large selection of older scanners. It's not free, but they do have a trial version that might get things working!