If you are unsure of where or how to install plugins, your best option is to use Lunarwater's Plugin Compendium. This application will automatically download and unzip many of the most popular plugins. Plugin Compendium will also allow you to keep track of updates and will facilitate downloading and unzipping updates. The application is available for Windows:
http://www.lotrointerface.com/downlo...ompendium.html
and Linux/Mac clients:
http://www.lotrointerface.com/downlo...mMacLinux.html