Simply select a theme and add your text. Choose from millions of free Creative Commons (legal to use!) background pictures or add your own images. You can also add public notes to share resources with your viewers and private notes to help you keep track of the things you want to include in your presentation. You have the ability to control privacy settings so people online see as much or as little of your "deck" as you want.
Even though this is featured as an iPad app, it is also available online and can be used with Macs and PCs. You do NOT need a user account to use the iPad app, but one is needed to create Haiku Decks with the web app.