Convert any presentation into a talking video: SlideTalk
Web app allows you to convert presentations into talking videos by using a text-to-speech conversion engine with multiple voices available in many languages. You just edit the text that needs to be spoken on any one slide and SlideTalk does the rest.
Final video clips are published freely on SlideTalk.net, to YouTube (with credits) and can also be downloaded (extra-credits).
Supports PowerPoint and image files.
Free version available. Limited to 30 slides.
Buy credits at apx $8 per presentation (30 slides) to do more.
Pricing info: http://slidetalk.net/Home/PricesCredits
My comment: Fantastic resource to create valuable video content out of your presentations. Effective, simple-to-use, reliable. Highly recommended.
Try it out now: http://slidetalk.net/
Examples: http://slidetalk.net/Home/Videos
Available voice samples: http://slidetalk.net/Home/VoiceSamples