If you want to upload a photo to a website from iPhoto, is there a simple way that you can access it, without having to export it from iPhoto first. When I navigate to the iPhoto folder, it just appears as an empty folder.
Starting with Leopard, you can use the media browser that is integrated with the Finder. Look at the bottom of the Finder's sidebar.
Explanation from Macword: Usage tips for the Leopard media browser
More details and nice screenshots in this InDesign-centric (but still applicable) explanation: Using the Mac OS Media Browser in InDesign
You can reveal a particular photo by control-clicking it within iPhoto, and selecting the "Show File" menu item in the contextual menu that pops up. That will reveal the actual image file for that photo in the Finder. I highly recommend not moving that file anywhere, since that will cause iPhoto to lose track of it, but you can copy it to another folder, attach to an e-mail, upload to a website, etc.
If you navigate to your iPhoto Library, Right Click and then select Show Package Contents you will be able to browse your library and select photos as normal.
This option won't be available from a website upload dialog box so you will have to copy photos out of there to somewhere convenient beforehand.