This is a c# project created in VS2010. In order to use it you simply add it as a reference to your umbraco package solution then add "UmbracoAutoPackager" to your post build event in your package project properties.
It locates the package.xml file in your package project and reads it in then uses it to discover the file dependancies. It creates the package zip file with all of the required files included. If there is a previous package zip file with the same name it archives it with a date time stamp. Finally it opens the folder containing the newly created package zip file with the file selected.