wp-confluence is a WordPress plugin that allows you to get page content from Atlassian's Confluence wiki software.
Download the plugin and place the 'wp-confluence' directory into your Wordpress plugins directory (usually '/wp-content/plugins/').
Once you've installed the plugin, activate it and you'll see a new 'Confluence' option in the 'Settings' menu. Customise the plugin for your requirements.
After you've added the Confluence settings in the new settings area, just add a new WordPress shortag to anywhere on your page with the page ID for the Confluence page you want to get the content from (e.g. [confluence id="1234"]) and this will pull the content out on the Confluence wiki and into your WordPress page.