How do I create skins for DooM2.
Do I need a special programe or something?

xwe, a paint program and one of the gbd2 skin wads would be a start; you can edit the skin into what you want and save it as something else (it's what I do)

I higly recommend deepsea!!! its the best doom editor in my opinion. It has all in one. It builds nodes, changes wads, changes maps, music, it does everything! Its really powerful and I know that several doom editors use it. You can find it at Doomworld.com, or search yahoo for Deepsea AND doom. ALSO, it will do skins!!! :d

deepsea is also shareware. You'll have to pay to get the full version. I think the shareware only supporst x number of sectors (the building blocks of levels… like LEGOs)