If you've got a cameraphone with more than one megapixel resolution, then you can take advantage of a cool free service called scanR. It lets you take photos of whiteboards, business cards, and documents and upload them via email to its website, where it cleans up the images and presents them back to you in both jpeg and PDF formats.
It's a great way to keep notes on strategy sessions (simply turn the jpeg-ed whiteboards into a powerpoint presentation and email it out to your colleagues) as well as keep track of receipts and papers you collect when you're out of the office. (TechCrunch has some pictures of what scanR is able to do.)
The PDF files of receipts and documents that ScanR created for me weren't searchable on the website, but by feeding them into a free OCR program like Microsoft Office Document Imaging, you can easily turn them into useful Word files. (Jon Galloway provides a tutorial here.)
