I don't know what program does Jeck Jims or other 3D modellers use, but I've used Misfit before and it does the job; you gotta learn 3 different skills to make a proper 3D model:
* Texturizing, basically giving the model colors and all that.
* Topologizing (or retopo with tris/triangles formed vertices)
* Animation, skeletal or topological, whichever you prefer, I've never used skeletal with that program, since it doesn't work very well with MD2; I also stuck with topological animation with MD3 (I won't upload any of them, they are not fresh in any way).
PS: It doesn't sound as a request but a question. I'd advice you to start playing around with other peoples md3 and making yours, not recoloring but actually modifying stuff from them (not uploading it, just using it as practice.)