The application is to be modeled after an existing iPhone app we developed a couple years ago. There are some changes we are to make to the iPhone app as well, which we will handle.
At a very high level, the application is intended to take pics of receipts, run the resulting pics through a 3rd party API that will detect borders, deskew, and convert to B/W. After the user has determined that they are happy with their receipt, they can answer some questions that may tag/classify the receipt. Finally, they save their receipt which ultimately sends the image and associated data to the server. There are also to be screens to view past receipts (sort/group), some reporting (most of which will be handled via SSRS and should be able to be retrieved within a webview control).
All communication will be via a WCF service using RESTFul methodology communicating with JSON messages.
We are looking to support gingerbread and up. 2.3.7. Normal screen sizes (not concerned about multiple layouts yet).
Testing is done by the developer, and periodic releases deployed to the client will allow any issues to be relayed back for changes.
Hope that gives you a good idea.