Among various approaches to the storage of hydrogen fuel for mobile applications, physisorption of hydrogen in porous materials is attractive primarily because of simple adsorption/desorption kinetics. The host material to strengthen its interaction with H2 was modified. These interactions were most effectively gauged by the hindered rotational energy levels of the H2 molecule, which can readily be observed by inelastic neutron scattering. Studies on sorbed H2 in zeolites, metal-organic framework compounds, and hybrid materials with unsaturated metal binding sites provided some direction for future porous hydrogen storage materials. This is an abstract of a paper presented at the 230th ACS National Meeting (Washington, DC 8/28/2005-9/1/2005).