Want to read a PDF in iBooks? This is how you do it for Mac OS X users (assumes iOS 4, iTunes 9.2):
- Create a folder called "PDF Services" in your Library folder (~/Library/PDF Services).
- Create an alias of iTunes (right-click on Applications/iTunes, click Make Alias).
- Drag the new alias (called iTunes alias) to PDF Services.
- Rename the alias to "Save PDF to iTunes".
Now you can "Save PDF to iTunes" in any app that understand what that means. So really, that's any app that can print. For instance, if you double-click on a PDF, it'll usually open in Preview. Click on File, Print..., PDF, Save PDF to iTunes. Now the PDF will be in iBooks next time you sync.