There is a special control in Silverlight responsible for scrolling of content. The full name of this control is System.Windows.Controls.ScrollViewer. You can use it like a regular container by placing all of the content you want to scroll inside of it. The control's properties that worth mentioning are two: HorizontalScrollBarVisibility and VerticalScrollBarVisibility. As you can guess they allow you to control the visibility of the vertical and horizontal scrollbars. The possible values are Auto, Disabled, Hidden and Visible.
Xaml
<ScrollViewer x:Name="scroller" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
<Image x:Name="scrollableImage" Source="SomeImage.jpg" Height="1000" Width="1000" />
</ScrollViewer>
That's it!