Microsoft Office Document Imaging (MODI) is a Microsoft Office application that supports editing documents scanned by Microsoft Office Document Scanning. It was first introduced in Microsoft Office XP and is included in later Office versions including Office 2007. It is no longer available in Office 2010. MODI allows users to Scan documents, recognize images using OCR, view a scanned document and Annotate scanned documents including using ink on a Tablet PC. (more: http://en.wikipedia.org/wiki/Microsoft_Office_Document_Imaging)
Free from Microsoft SharePoint Designer 2007 (freeware), MS Office XP/2007 contains this too.