I used a web application called Authorstream (see an earlier post titled Create An Online Talking Book) to embed a PowerPoint presentation on my main English webpage. We shared it at a wonderful year-end celebration for our English Language Learner students.
The main difference, I believe (but am not sure and am very open to being corrected) is that you can also upload audio with your PowerPoint on Authorstream. This creates the possibility of making “Talking Books.”
However, it is possible you can do the same with some of the other web applications listed and I just haven’t figured it out yet.