A new feature in Microsoft PowerPoint 2010 allows you to broadcast slide shows to remote viewers over the web. All you need is a Windows Live ID. Microsoft provides a free Broadcast service, and creates the URL for you to share with your viewers. Just click File, Save & Send, Broadcast Slide Show, Broadcast Slide Show.
For more details, read our Microsoft PowerPoint tip: Broadcast Microsoft PowerPoint Slide Shows to Remote Viewers for Free using Windows Live ID