Installation couldn't get any easier. Once downloaded, simply...
- Unzip the archive.
- Copy the extracted folder named curreX into your WordPress plug-ins folder.
- Activate the plug-in from the Plug-in Manager in WordPress.
- Visit the Sidebar Widgets page under Presentation menu (for upto WordPress 2.3.x) OR the Widgets section under Design menu (for WordPress 2.5.x) to drag & drop the widget onto any sidebar you desire.
- Configure the widget as you like (Source / Destination Currecy, Decimal Precision etc.) and Save changes.