You can get the latest Version of the Plugin for Moodle from the Moodle Plugin database .
You simply download the ZIP or TAR package and unzip it to Moodle's "mod" directory.
Eventually you need to unzip the package into a folder called "openmeetings".
The folder structure is:
$MOODLE_HOME/mod/openmeetings/*.php
Then you visit the admin interface of Moodle, for example http://$your_moodle_host/$MOODLE_WWW_ROOT/admin
Moodle will detect that there is a new plugin and will show the plugin installation screen:
After you have clicked on "Update database" Moodle will show you the plugin configuration screen: