I know there are a lot of iBooks questions, but I haven't found this one anywhere. I have PDF files on my PC that I want to get on my iPad. Before I would just drop them into iTunes, and plug the iPad in to the PC, and it synced fine. Then I updated to ios5. I was under the impression that I wouldn't have to plug the iPad in anymore. I'm still dragging and dropping the files like normal into iTunes, but they don't show up in the iPad. These are not files I purchased from iTunes, to be clear. I'm also sure I have the "sync collections and bookmarks" options checked.