I've had to do this several times for companies I have worked for. I started actually with a scanner to scan in some old spread sheets that someone had printed. Then I converted them back into spreadsheets with Omnipage (8 or 9 back then).
A couple years later, I started scanning all customer contracts and account documents and mapping them out with MindManager to keep things organized.

These days I have my own company, so everything gets scanned. I use PaperPort for document management and I use OmniPage 16 these days for OCR purposes.

I've got a three hundred dollar Brother scanner/copier/fax/laser printer that I keep on the dock that is fantastic. I just drop a pile of papers into the document feeder and scan away.