This plugin is very simple and straightforward. Just enter ?{list}? on each parent page or post where you want the children listed. Put it anywhere in your content and that is where it will show.
Then in your css..
.subpage-style { Put your styles here };
Easy as pie!

Andy's List Subpages Plugin

Nice and simple plugin that lists the children of a certain page or post in…

MyWebsiteAdvisor

ChrisHurst

Use the [children-excerpt] shortcode where you want to display the excerpts of the child pages. 
Defaults to the first 50 words, can be overridden with length attribute so your excerpts can be set to any length of your choosing.
Developer Website: http://MyWebsiteAdvisor.com
Plugin Page: http://mywebsiteadvisor.com/tools/wordpress-plugins/children-excerpt-shortcode/
Video Tutorial: http://mywebsiteadvisor.com/learning/video-tutorials/children-shortcode-plugins-tutorial/
Requirements:
To-do:

Name: Children Excerpt Shortcode

Use the [children-excerpt] shortcode where you want to display the excerpts of the child pages.

Andy's List Subpages Plugin vs Name: Children Excerpt Shortcode