A solar cell includes an improved anti-reflection (AR) coating provided on an incident glass substrate. In certain example embodiments, the AR coating includes a layer comprising porous silica. The porous nature of the silica inclusive layer permits the refractive index (n) of the silica inclusive layer to be reduced, thereby decreasing reflection and permitting more radiation to make its way to the active layer(s) of the solar cell. In certain example embodiments, a coating solution may be formed by mixing a colloidal silica solution and a polymeric silica solution, then applying the coating solution to a substrate and curing the same in order to form an AR coating.