Originally Posted by yvanleterrible
The iPad does not support a hierachical file system yet. That will be with OS4 next fall.
This is not true, or more precisely this is confusing.
Come OS4, iPad/iPhone will gain support for folders solely for arranging apps on the home screen. Nothing to do with the file system.
Getting media onto the device will still have to go through iTunes, although you will also be able to have a shared directory on the device that can be accessed by any app that is written with awareness of the feature.
In answer to the original post, the best way to get your PC folders of photos onto your iPad/iPhone etc is using Adobe Photoshop Album 1.0 or Adobe Photoshop Elements 3.0: http://support.apple.com/kb/HT1389
Let us know how you get on.