I'd say it's easy if you know what you are doing. Some background knowledge of 3d models is required, and how to make proper frame animations.
What I did to get to learn how to make md2s, is use the well-known program 'Misfit 3d' and learned all the tools and settings there, then I simply made frame animations of a model following the frames that a character wad has. If you are determined to actually try and stick with it, you could pm me and I'll respond a full response on how to properly make a md2 model, and how to make it work in srb2.