Upstage is a new mobile application for developers and designers which allows you to easily share iOS app mockups with other team members and external clients. The app has was originally developed as an internal collaboration tool by the folks over at Boxcar, the push notification provider for iPhone, iPad and iPod Touch whose own mobile app is a perennial favorite here at ReadWriteWeb.

With Upstage, now in public beta, any mobile developer or designer working on iOS applications has access to this tool for free.

Why Upstage?

According to Boxcar's CEO Jonathan George, Upstage was built out of a real need iOS designers and developers have today. These team members are continually trying to keep track of ideas, screens and approved designs all in one place, and they need to make those easy to access from wherever they are. They also need to clearly and quickly communicate which designs have been approved for development and which are still in progress. Upstage makes all this possible.

Previously, the team at Boxcar was using general purpose tools like Google Apps and 37Signals' Basecamp product to communicate with each other. While both of those can be used as project management tools, it's easy to lose important messages about design approvals in various message threads, said George. Something simpler was needed - a single-purpose app designed to address just this specific need.

At Boxcar, the company believes in the "design before development" philosophy, so Upstage fits right in. The app makes it easy to communicate between teams, as the designers will sign-off on screens before the developers begin to implement the changes.

It has also been used to present designs to its board for major upcoming product changes, says George.

How to Use Upstage

Using the app is simple, too. To begin, you just create a project, name it, upload an image (like the logo) and select the project type (iPhone or iPad). After the project is set up, you can use the included file uploader to select an image from your computer and upload it as your first screen. The company has even gone so far as to provide a helpful list of design and development resources on its website, including an online cheat sheet of Apple interface sizes.

For now, there is no charge for developers and designers interested in using this product, although the company may choose to charge for it in the future. In the meantime, says Scott Taylor, who created the app along with Jeff Boulet, they're already working on several new, and much larger, features planned for a future release. No word on what those may be just yet.

If you're interested in trying Upstage yourself, just head over to the website and sign up for an account here.