Zoom In,Zoom Out

Hi,
I am using OpenGl and VC++.
I am displaying the texture using Triangles and then calculating the normals and normalizing them to obtain a smooth surface.
I would like to add features like zoom in & zoom out…how can I add these feature.
Do i need to translate in order to zoom in & zoom out.

Thanks
aus

I believe that translation will work, though it might cause difficulties with the near clip plane
I think that most people simple narrow or widen the FOV