No, it's not the only iPhone webapp available.
I would start at a great iPhone webapp Manager that was created by Matthew Peach: http://matthewpeach.com/iphone/
It has a lot of iPhone apps listed and lets you manage them on your iPhone. And it has a great iPhone like interface.
Don't forget AddFone (www.addfone.com), a search engine for iPhone related apps that has the largest database of apps around (almost 50% more apps than the second large list).
