For example, you want to embed the 3gp video of "Google I/O 2012 - What's New in Android?" in your app.
Right click the video to copy Video URL.
Paste and open the link, replace the leading "www.youtube.com" with "m.youtube.com" to get the mobile version.
Corresponding mobile version of the video will be loaded. Right click on the video to Copy Link Address. It's the 3gp link of the video:
You can copy this link to replace SrcPath in the example "A simple example using VideoView to play 3gp from YouTube".