WordPress.org

1. Unzip just-widget-link.zip
2. Upload the just-widget-link directory and all its contents into your /wp-content/plugins/ directory
3. Activate the plugin through the 'Plugins' menu in WordPress
4. Use the widget admin page to add the widget to one or more of your sidebars and configure it

Where should I ask questions?

http://justfly.idv.tw/2009/06/06/Just_652.html

Use comments.

I will answer only on that page so that all users can benefit from the answer. So please come back to see the answer or subscribe to that page's post comments.