I remember inoblivion there was the need of a weird tool that made some niutrishape deformation stuff , is that still the case ? or is easier just modeling and implementing?

Weird tool is probably the conformulator.

Exactly .... is it still needed ? and is there any tut onhwo to make hairS?

Making hair is just like any other skinned mesh workflow, except a few things. I authored some files to help with creating .tri files using conformulator and wrote some notes there as well. http://www.skyrimnexus.com/downloads/file.php?id=6402

Read and downloaded , and endorsed but I honestly didn't understand much of what I need to do with the conformulator .. if is needed or not , I just want to make those hairs .....

http://www.conan.com/content/gallery/barbarian1.jpg

Late reply...

You only need to use the conformulator if the hair or hairline model sits close to the base of the neck. Heads have _0 and _1 morphs much like bodies do, and the neck bulges up for the muscled look. Also, remember that heads work backwards. What you see in malehead.nif is the _1, the _0 (SkinnyMorph) is inside the tri file.

what you mean by backward? I usually load the _1 file for the bodies to work armors on then morph to a _0 shape , isn't the same for hairs? also when I did edit a bit the long hairs I just moved some vertices around on a _1 shape I guess and reexported but still Seems I didn't broke anything as the hairs still worked fine ... wich surprises me actually ... so the conformulator is only for neck surrounding hairs? what if I make instead of the conforumulator a _0 version?

Backward in how my brain thinks, at least. I see _0 as the base, and _1 as sequential to that. So following my logic, head.nif would be _0, and head.tri would be _1, but it's actually backwards.

And I don't think heads/hair can use _0/_1, only the tri morphs, it would be too messy, I think.