PowerPoint 2013 allows you to export into a video (MP4 or WMV). Why a video, you ask? Why not just give the PPT with audio to the students in .ppt form? The main reason is to avoid technical problems that the students may have, since not everyone has PPT, not everyone will know how to play the audio, and the file size will be large. Trust me!
Here is a video I made showing this and below are text instructions:
1. Design your PowerPoint following best practices, such as one concept per slide, the use of graphics/images that back up your point, very limited text on the slide, etc. Here is a video I created on this topic.
2. Add your audio. This process is the same in 2013 as it was in 2010 if you did it there.
Note: I have experienced a lot of problems with the correct mic working in PPT 2013. It's very odd. I have had to disable the internal mic on multiple laptops in order for them to use the headset mic. I'll make a video showing this. Regardless, I highly recommend recording just one slide and then listening to it and making sure all is well. Recording an entire presentation with horrible or no audio is very frustrating.
2a. Under the SlideShow tab, choose Record Slide Show. You can record from the beginning or from the current slide (you'd have to click on the slide you want to record before doing this). This is a fantastic feature because it is easy to edit slide by slide later, since PPT breaks the audio down into individual slides.
2b. Leave the settings on the next dialog box both checked. Laser pointer motions are kept in the final recording so you can use that if you want. You can also use your animations. I highly recommend the appropriate use of animations here and there to make text or images appear exactly when you refer to them.
2c. Click Start Recording. The PowerPoint will go into full screen and will automatically start recording, so make sure your headset is all ready to go. (You can trim the beginning or end of your audio afterward via the Playback tab when you've clicked on the speaker. Cool, huh?) Remember to keep each slide at a minute or less!
2d. A recording short cut menu appears at the top left of your screen. Here is a screenshot with a description of the buttons typed in blue. The arrow going back is a "redo" button you can click if you want to start over on the slide. I assume the pause button is universally understood :)
2e. IMPORTANT: Only record a slide or two and then get out and listen to make sure your mic is working properly!!!
3. Export your PowerPoint as a Video.
3a. Click the File tab on the top left.
3b. Then click Export
3c. Create a Video. Make sure it's on "Use Recorded Timings and Narrations. I have been leaving it on the Large display option and it's fine.
3d. Click Create Video again and choose your file type.
The progress window is pretty subtle. You'll see the image below at the bottom of your PowerPoint. The white area will progress. It can take a while to export; be patient and avoid making the computer do much else during this time.
4. Upload to YouTube, or whatever streaming service you prefer. (Yes, this is required because the file is probably pretty big).