As any Joomla! developer will know, its great fun creating the template/module/plugin or component but not fun having to manually write that list of files into the xml file afterwards! Here is a solution, the module above will simply let you upload a .zip (without your .xml file and then it will parse through the .zip and then output some clean XML file list for you automatically.
All you need to do is select template or module, and specify a module name if you chose module. The program will do the rest, if you have a component or plugin, unfortunately I haven't encorporated those yet, but if you use the XML creator for 'template' it will atleast give you the full list of files, this will potentially save you a lot of time when creating a templateDetails.xml or a general addon XML file.
Any problems or errors please leave them in the comments or in the forums, thankyou. The download is below if you wish to use it on your own site.