Tension Software (http://www.tensionsoftware.com) has released version 2.1.1 of Product Builder, a Mac OS X app targeted to developers. It allows users to create packages ready to be transmitted using the Application Loader (by Apple and included with the Developer tools) to the Mac App Store.
Version 2.1.1 is a maintenance upgrade. Product Builder costs $2.99 and is available at the Mac App store. It requires Mac OS X 10.10 or higher.