Getting PDFs into iTunes to sync them with iBooks on your device can be a bit of a chore. But by using the method below, you can send any document or even web page straight to the Books section of iTunes for syncing with ease.
To get iTunes ready is simple. All you have to do is open your Applications folder, and make an alias of iTunes by control-clicking its icon and selecting ‘Make Alias’. Now drag your newly-created alias and drop it in [Your Home folder] → Library → PDF Services. What this does is adds iTunes as an option when you select the PDF button in a Print dialog.
At the moment when you click PDF under Print, it’s going to say ‘iTunes alias’, which isn’t very informative. Rename your iTunes alias in the Finder to something along the lines of ‘Send PDF to iTunes’ or ‘Add PDF to iTunes’ and the menu item in the Pront dialog should update next time you open it.
Now whenever you have a document or web page open that you’d like to read in iBooks, all you have to do is go to File → Print, then click the PDF button in the lower left and choose your menu item for iTunes. The document will be saved as a PDF and sent straight into the Books section of your iTunes library.
This method works for any application that can open PDF files, not just iTunes.