PPeelen

This plugin lets you add your app’s position on the appstore to your blog. Simple add the Apple ID, select genre and range and your on the go.

Itunes AppStore App Ranking

This plugin lets you add your app's position on the appstore to your blog. Simple add the Apple ID, select genre and range and your on the go.

gilthonwe

This plugin allows you to use the shortcode <code>ios_app_review</code> to embed iOS app reviews and ratings directly into your blog.
What does it do? 
The first time a page with the shortcode is loaded, the plugin will try to download the reviews from Apple’s servers. Then it will store them in a file and nicely display them on your page. 
Every time someone opens the page, instead of downloading the reviews again, the plugin will read them from the cache file. If the cache file is too old, the plugin will try to download new reviews from Apple’s servers.
Check out some examples of what it produces here: http://www.gilthonwe.com (My iOS Apps section)

AppStore Reviews Viewer

Adds a shortcode that displays reviews and ratings of an app from the iOS AppStore’s country you chose.

Itunes AppStore App Ranking vs AppStore Reviews Viewer