Oh, right - That makes a bit more sense!
Each file you add as an embedded resource is available via the Properties.Resources. So, if for example you add a flv file called MyYouTube.flv to your Resources as an embedded resource:
object res = Properties.Resources.MyYouTube;
If you look at the object it will be an array of bytes, so you can just save it:
fileName = Path.GetTempFileName();
File.WriteAllBytes(fileName, (byte[] res);
If you save the file name in your class, then handle the FormClosing event, you can delete the temporary file when you are done.