If thou gazest long into the Pit, the Pit will also gaze into thee

Please leave your HTML wizardry at the door - your powers are of no use here. BBCode is similar to HTML in basic structure - but entirely different as far as persnickety syntax goes. Relax, it's not a steep learning curve (minor stuff like square brackets instead of angled ones, no quotes for URLs etc.) and there are buttons for most common things. Here are some quick start guides -

BBCode Guide
BBCode tags reference

YouTube Embedding Tutorial

Ok, here's how you do it. A youtube video url will come in two different types. The kind with the video code at the end, and the kind with the code in the middle. You need to strip off this extra stuff before putting the code (alone) between the youtube tags.

Here are two different urls going to the same video: Always get rid of everything up to and including, the first (or only) equal sign "=".
The stuff after it is the code, but note in the second example, there is extra stuff after the code.
The extra stuff after always begins with an "&" followed by whatever extra stuff.
Strip off the &'s and the extra stuff following at the end.

To sum it up, just keep the part between the first "=" and the first "&" (if there is one).

We are left with just the code: xC03hmS1Brk so... The above tag and code will become this when posted:

[youtube]xC03hmS1Brk[/youtube]