Packaging a component for distribution is relatively easy. All front-end files are places within a directory called /site and all administration files are placed within a directory called /admin. Here's what a typical package will look like:

/com_{componentname}
  {componentname}.xml
  /site
    {componentname}.php
    controller.php
    /views
      /{viewname}
        /tmpl
          default.php
    /models
      {modelname}.php
    /controllers
      {controllername}.php
  /admin
    {componentname}.php
    controller.php
    /views
      /{viewname}
        /tmpl
          default.php
    /models
      {modelname}.php
    /controllers
      {controllername}.php

Just "zip" up the primary directory into a compressed archive file. When the ZIP file is installed, the language file is copied to /language/{LanguageName}/{LanguageName}.{ComponentName}.ini and is loaded each time the module is loaded. All of the other files are copied to the /components/{ComponentName} and /administrator/components/{ComponentName}directories of the Joomla! installation.