Power Point is the most commonly used presentation software in both the education and business worlds.  It now changes URL's for you, exactly as word processors.  If you want to link to a URL without showing the actual URL, type the words you want to show into the "text to display" box.  That is how I linked to the same URL from the words "Owl Mail".

When presenting, you click on the link to open a live browser and view the Internet page. 

This means you must have your computer hooked up to a live modem or Ethernet connection.  Checking this and the projector are very important, night before, preparations when planning a presentation. 

To continue your presentation after viewing the web site, minimize or close your browser window.  This returns you to the presentation window, which should have remained underneath on the page you just left.