What options do I have for an image scanning framework on Mac OS X? I'm not looking for an OCR library. Just something that will do the actual scanning and importing to PDF or comparable format.
On Snow Leopard and later, Image Kit includes classes for scanning and importing from cameras. There's also a lower-level framework, ImageCaptureCore. Both frameworks are documented in the Image Capture Applications Programming Guide in Apple's Documentation Archive.
On Leopard, you'll have to use Image Capture, the less-documented, less-modern, less-reliable API. (This stands in contrast to the Image Capture application, which has always been great.) I hope you can require Snow Leopard.