In case you do not know how to work with photoshop. I don't know how that skin editing works but if has something envolved with paint (for example lol) I advice you to get photoshop and practice 1st.
It doesn't really matter if you use PhotoShop, Paint, GIMP or any other Image manipulation program because the only thing you do is exporting the file to .TGA, open it in a IMP, use a round brush to make the handle blue, and a text tool add the text.. Save the .TGA, Import it to VTFEdit and save.
Drag and drop the file to .../counter-strike source/cstrike/materials/models/weapons/v_models/ (You might need to create some folders)
Hmm. Well thanks Espen for the nice comment And yes i will try to make a NoD 69 deagle. And thanks for all the comments ppl now i can improve my work and try for bigger things...