Can someone please tell me how to post a YouTube video to my WordPress blog? What about adding multiple YouTube videos playing in the same area with a menu to choose which video to play?

1. At the bottom of all YouTube videos pages you find a "Share" button. Click on it and choose "Embed" then copy the code. Example:

<iframe width="560" height="315" src="http://www.youtube.com/embed/4Fr5-16ZnPM" frameborder="0" allowfullscreen></iframe>

2. All you need to do is copy the code and paste it into your post or page.

Adding multiple YouTube videos playing in the same area with a menu to choose which video to play

Here's an example...

Choose the video you would like to watch from the following menu:

Steve Jobs
Katie Melua
Paramore
Almost Famous

How this is done is described in my WPFAQ.org E-Book (sample)