If you got a presentation containing a movie inside a PowerPoint file, then you can export it, for example if you need to upload it later to YouTube or embed it in another slide. To export a movie from powerpoint 2010 you can open the .pptx file using a tool like WinRAR or WinZip and then browse the archive until finding the multimedia video. Since .pptx files are just compressed archives then you can use these tools to decompress the content.
If you need to export the movie programmatically, for example using C# then you can use a similar approach and open the .pptx as an archive (ie. using a Zip library like DotNetZip from Codeplex to compress and decompress files with .NET) and then browse for the .avi or .wml files under the archive. This is good for example if you plan to use the MS Office PIA.
Read more: Download free zip powerpoint template or how to upload a presentation to YouTube.