I wanna start making mods with custom armor. I have quite many good models (from oblivion and other MMO games), but i have little problem: http://www.moddb.com/members/sgaorion/images/armor-problem .Have not find a solution in the internet yet, so could someone plz tell me how to make the helm work well? I would really appreciate that. Srry for some bad english lol.

load a head in nifskope, and then copy and paste the helmet there.
Move and rotate the helmet so it fits the head.
Delete finally the head.

Tyvm:)

But how i can see the Armor and Shields? is there any sort of tutorial somewhere?:)

about shields, you can load a shield in nifskope, and place your own in the same file, and move it...
about armor you can do the same, but not with the cuirass and gauntlets.... you have to know how to weight paint the meshes.
You can do it in blender, if you are familiar with it.