Early phases of the project
Once we've gotten some ideas about the project scope, and signed all the appropriate paperwork, we begin the early phases of the project.
Development typically begins with getting a "wireframe" application to the client to preview. A wireframe has the general look and feel of the finished app, but may be missing nearly all of the functionality. This allows the client to view the app flow on a device, play with it, and specify any desired changes before things get too far along.
After that, you will receive a weekly report with details about progress made and every other week, you will be invoiced for the prior 2 weeks' worth of work. You may also receive an email or two during the week asking for clarification of some detail, describing mid-week progress or reminding you about your next action in the process (i.e., signing-up with the iTunes Store to be able to distribute iPhone apps.)
Once all the details are worked out, you will be well into the middle of the project.