We've had a few members recently that have been having problems posting Youtube videos. Generally, on the Youtube video page, you need only click the "Share" button, then click on "Embed". Copy and paste that code directly into a post here and the video should display right in your post.

Now, if you're having issues with that, here is an alternative, or 2:

1 - On the Youtube video page, copy the URL at the top of the page, the actual address where you are viewing the video. For example, here is a URL:

Code:
http://www.youtube.com/watch?v=lMTrthePKU0
While creating a post here - click on this image ---->

Past the actual address in that box, and the video should appear in your post when you post it.

2 - Alternatively, just copy the address into your post, and add the video tags around your URL, like such: