WP Slideshow - The most costumizable and stylable Slideshow Plugin for WordPress. Duration, Speed and Styling - You can configure by yourself. Widget
You can Insert WP Slideshow everywhere! For Example under your Navigation Bar, in your Footer, Sidebar etc.
You don't have to edit the Stylesheet you can make changes directly in your Administration Panel (Settings --> WP Slideshow)
Defautlt Resolution for the pictures is 400x250. Keep in mind that, when you change width and height you have to change the resolution of your Images as well.