Uh-oh. I wish I had seen this post before I wasted money on the IPOD app last week.
My IPOD is my primary ubiquitous GTD device since it goes everywhere I do, allowing for on-the-go collection, processing, organizing, and changes, and spur-of-the-moment quick reviews.
My Desktop is secondary; with its planned use to be bulk-entry of backlogged home items and thoughts, and as backup for the ipod. As I collect and work through piles of "my stuff", things were to be moved to the IPOD. It will probably be my central Detailed Review device since keyboard entry is easier and home is more peaceful than anywhere else. But, I have not yet setup sync between them.
Please make a plan to develop the iphone/ipod application to have the same functionality as and properly sync with desktop.