One current limitation of the iPhone is an inability to download and store documents.
If you have the time and ability, storing PDFs onto a web page will provide you with the best iPhone viewing opportunity, but you will have to be internet connected to be able to view them.One tip to actually store documents (PDF, Word, Excel) locally comes from dharrison9 on our forums. He noticed that Yahoo push email accounts actually download and save documents locally rather than relying on server downloads with each view. This means you can view your documents offline. The steps are as follows:
To download documents to your iPhone for later use (later being when you don't have a connection to the Web):
1. Start a free Yahoo! Email Account.
2. Set it up on your iPhone (Settings, Mail, Add Account).
3. Email the Yahoo! Address the file you want to save.
4. The Yahoo! account will 'push' the attachment to you and save it for later viewing.
5. The iPhone's Mail application just became a document viewer!
Not without limitation, Mail's PDF/Document viewer only allows you to view documents in portrait and not in landscape. This requires you to pan/scan through the document to read it.
An alternative hint comes from G4R2 who points out that Mac OS X offers a "Save PDF to iPhoto" option in all printable documents. By printing to iPhoto, users can choose to sync these documents in iPhoto. While the resultant documents are viewable in both Portrait or Landscape, iTunes automatically reduces the resolution on images coming through iPhoto. This makes small text very difficult to read on the iPhone's Photo viewer. Instructions for this procedure are provided:
1. Open the PDF file you want to view on your iPhone in Preview in OS X.
2. Select Print. In the dialog that appears select the PDF button on the bottom left hand side.
3. Now scroll down the pop up list and select Save PDF to iPhoto.
4. iPhoto will now launch and you will be prompted for an album name to store the new files. Type in the name of the document or if you prefer just "iPhone Documents" if you'd like to make this album the repository of all your converted documents.
5. Sync your iPhone. You'll have to go to the Photo page in iTunes to make sure the folder is selected and that the images sync.
6. On your iPhone click photos and you'll see the PDF has been broken down by pages and is viewable, scrollable, and zoomable like any other photo.