This plugin helps you to self-host your WordPress plugins on your own site. It even uses an extend/plugins/ structure
There are a few things that you need to do to make sure that you can use this plugin.
This plugin makes use of the ZipArchive class, introduced in PHP 5.2.0. You must be running at least this version to use the plugin
I develop plugins using a framework that I've developed for allowing rapid database-driven plugin development. The Self Hosted Plugins uses that framework, so you must install the Top Quark Architecture plugin.
Like plugins hosted on wordpress.org, you must include a valid readme.txt file and the proper plugin headers in your main plugin file. Check out a sample readme.txt file and use the readme validator. The Self Hosted Plugins plugin uses the readme.txt file and the plugin headers to render information about the plugin.
Thanks to Janis Elsts for the
plugin-update-checker.class.php file. See http://w-shadow.com/blog/2010/09/02/automatic-updates-for-any-plugin/
Thanks also to all members of the wordpress-plugin-readme-parser project. This code lets mere mortals parse a readme.txt file