Texturing program or unwrapping program?
If you really mean texturing then Photoshop (coupled with Max) is still the best to me...
But I think you're more looking for something like Bodypaint 3D. It allows you to work on the UVs and to directly paint on the actual 3D model...
There's also another one wich wasn't too bad but it's much older and I don't remeber the name, sorry.