PDFpen

PDFpen lets you fill in PDF forms and add your signature. I have been using to sign forms for my kids off at boarding school. It adds more functionality over what you can do with preview. The new version adds OCR capabilities (haven't tried this yet). As a radiologist at a hospital, I don't have an office, but it looks like it might help with the e-paper shuffle between EMR systems.

http://www.smileonmymac.com/PDFpen/index.html