WordPress.org

Upload the plugin to your wp-content/plugins folder and activate it.
To get a list of the plugins that are installed and activated in your website, insert the following into any post or page:

<ul>
[plugins_list]
 </ul>

You can customise the output specifying the format argument. Here's an example:

<table>
    <tr>
        <th>Title</th><th>Author</th>
    </tr>
    [plugins_list format="<tr><td>#LinkedTitle#</td><td>#LinkedAuthor#</td></tr>"]
</table>

The placeholders are: #Title#, #PluginURI#, #Author#" ,#AuthorURI#, #Version#, #Description#, #LinkedTitle#, #LinkedAuthor#. I guess their meaning is self evident.

If, for some obscure reason (I cannot think of any), you want to list also the plug-ins you have installed but are not using, here's the formula:

<ul>
[plugins_list show_inactive='true']
</ul>

The plugins list can be freely styled with css, just place any class or id attribute on the format string, or on the elements surrounding it.