A couple of months ago I had a post about pgn readers for the iPad. The reader I mentioned was Chess Viewer from Everyman Chess, but I also noted that you could only access pgn files from the web.
Turns out this isn't the only way. If you use Dropbox, you can save your own pgn files on one computer (your home computer for example), and then open them on your iPad. At first it will complain that there is no application that will read them, but if you choose the 'Open with' option (at the top right of the screen), you can then choose Chess Viewer (or your own installed pgn reader) and the file automatically becomes available to use.