If you make an alias of the iTunes application icon and place it in your ~/Library/PDF Services folder (where ~ = your user account), you can choose to print any document or webpage as a PDF directly to your portable device the next time you sync.[Simply select the print command and click on the PDF button on the bottom left and then choose iTunes from the drop down list. When you go to sync your portable device, be certain that, in iTunes, with your device selected, the “Books” tab is selected and you have checked “Sync Books.” Then simply sync your device. Poof! The PDF file(s) appear in iBooks on your device.]
I’ve tried this, and it actually works! Nifty.
Other little scripts are available to do similar things with various twists. Check out this link at Doug’s AppleScripts for iTunes.