I wanted to do a writeup of my quest to build and launch my first iPhone app in Apple's App Store, but already more than a week has passed since my app was declared "Ready for Sale".
The application is a simple utility to monitor the Amazon sales rank of any item that's for sale on Amazon.com.
Other uses, in order of keyword interest I've seen: book sales rank, dvd sales rank, cd sales rank, game sales rank, album sales rank.
Read more about Ranktouch at the promo site.
The application doesn't yet interface with Rankforest, though it might eventually if there's interest. It runs stand-alone, collecting data from Amazon for any title(s) you provide an ISBN/ASIN for. If you don't have an iPhone/Touch or simply want more advanced Amazon sales statistics in web app form, try Rankforest for free.