Lighting and rendering human faces

Hello,

I am trying to render 3D human triangulated face meshes. I am able to get them rendered with the texture on them. But since the mesh is triangulated at a low resolution, once lighted, it appears very jagged and triangulated. Is there a way to light this mesh without it appearing jagged/triangulated? Such that the light will affect the triangles in a gradual or interpolated fashion versus lighting each triangle to one absolute value? Preferably without having to smooth the mesh because that would probably be a hassle!

Here is a picture of what my current rendering looks like:

http://i1229.photobucket.com/albums/ee479/Big_cloud/Screenshot2012-03-21at10544PM.png

Thank you very much!