Author of plugins: Rob Marsh

Functionality: Popular Posts displays a list of your blog’s most-viewed posts. The output can be customised.

Requirements: This plugin requires the latest version of the Post-Plugin Library: download it now.

Download it here.

Installation Instruction:

# Go to the Plugins page and activate the plugin.
# Put <?php popular_posts(); ?> at the place in your template where you want the list to appear or use the plugin as a widget.
# Use the Options/Settings page to adjust the behaviour of the plugin.

Complete instruction can be found here.