incrediBILL - 8:38 pm on Aug 5, 2012 (gmt 0)
Hi Valdo909, and welcome to WebmasterWorld. Yes, if you're trying to learn HTML and CSS you should obviously learn the latest version which is HTML 5 and CSS 3 otherwise you'll be learning old technology.
HTML 5 is what all the new browsers and cell phones run, you can make responsive websites that resize and change based on the scale of the device.
To speed you along, you may want to start with an HTML 5 framework, there are many. I personally like Twitter Bootstrap as it has EVERYTHING you need to do just about anything. I was impressed.