Once I installed a trial of Microsoft Office 2003 (or was it 2007?). Anyway, when I had to uninstall it, somehow I managed to keep the "Microsoft Office Document Imaging" tool.
BTW, everyone who owns any part of Microsoft Office has this tool on his PC.
This is a marvelous OCR software. Incredibly fast and VERY accurate (powered by Scansoft).
Hth,
David.P