Analytics App for the iPhone stands out from it's competitors which are clunky and badly implemented in comparrison.
It gives mobile access to the Google Analytics data for your sites and supports multiple accounts. The home screen lists all your linked accounts, which requires submission of your google account details.
Drilling into a site profile exposes a variety of useful reports. The Today view lists unique visitors, traffic sources, popular pages etc. Further tabs allow access to most of the really useful data housed in your analytics account. You may filter all reports by date range.
Overall the app offers a great quick overview of your site(s) traffic without uneccesary complication. The interface is well optimised for the iPhone and the delivery of data is fast.
Well worth the money and presently best of breed.