How To Licence Apps Done With Yii And Tutorials About Yii Dev?

Hi there,

So, as I can see Yii is released under BSD Licence. What I would like to know is: how should I licence the applications I make with Yii ? Do they need to be BSD also or what ?

Next thing, if I make some tutorial about developing apps with Yii, how should I licence them ? GFDL ? And can I point to Yii documentation as a reference, or other tutorials ?

I am quite new to this, coz I have never done any licencing my own. I have one more question that is not so much related to Yii, if you would be so kind to help me.

How do you do licencing at first place ? Is it enough just to copy/paste the licence text in your code or something, or you need to register your code/apps/logos/trademars at some organization ?

Sorry for bad English.