MCSkin3D

MCSkin3D is both a skin management and skin editing tool. It holds all of your skins in a convenient place, lets you manage them from within the program, and even lets you upload your skin directly to Minecraft.net without ever needing to open a browser.

MCSkin3D was inspired by several sources, notably Q2MDL, an old Quake 2 skinning tool, SkinEdit, an excellent 2d skinning program for Minecraft, as well as modern editing tools such as The GIMP.
With art and sample/template skins from whtdragon, you're sure to have the best samples and templates to help you get started with your skins!