>I have a client that would like to be able to scan documents through the program and also be able to call up documents and open them within a window on a form. Any suggestions for the best way to do that? They would be using individual desktop scanners.

I assume everybody is using the same kind of scanner. Check the scanner website to see if they have some kind of SDK for the scanners. I don't think there is a standard API or DLL for scanning (but it wouldn't hurt to check).
The scanner will output an image that you can save on disk or in a db. To display the image in a winform just use the picturebox or the browser control (browser control can display PDF files if Adobe is installed)

Einar