OK, I totally stole this from the
DocumentSnap blog, where it was configured as a folder action, but I was surprised when I couldn't find a print-to-inbox script on this forum. To use the script, open it in AppleScript Editor and save it as a script (.scpt extension, not .applescript which is text) to ~/Library/PDF Services/ . Once you've done that, it will show up in the PDF menu at the bottom of expanded Print dialog boxes, and you'll be able to stick anything you can print directly into your OmniFocus inbox.