To include advertisement in your Windows 8 Apps (including the phone apps) see the article at:

http://msdn.microsoft.com/en-US/library/hh506371%28v=msads.10%29.aspx

For the walkthrough on using Advertisements in your XAML Based apps:

http://msdn.microsoft.com/en-US/library/jj157022(v=msads.10).aspx

You will find the Advertisements use more colors and images then the ones you used in Windows Phone.