List Category Posts is a simple plugin which allows you to list posts from a category into a post/page using the [catlist] shortcode. This shortcode accepts a category name or id, the order in which you want the posts to display, and the number of posts to display. You can use [catlist] as many times as needed with different arguments.
Great to use WordPress as a CMS, and create pages with several categories posts.
It includes a widget, which works pretty much the same as the plugin. Just add as many widgets as you want, and select all the available options from the Appearence > Widgets page.