Ultrafast angle-resolved two-photon photoemission (TPPE) is used to probe the electronic structure of highly ordered monolayers of organic materials deposited on the Ag(111) and Ag(100) surfaces. Studies focus on how the electronic states intrinsic to the silver surface are perturbed by the presence of the organic adlayer. These studies show that the strength of the interaction between the surface states and the organic adlayer depends on the nature of the surface state being investigated. For states localized at or near the organic adlayer, substantial changes in the surface state band structure were discovered, whereas for states residing farther in the vacuum the surface state band structure was perturbed surprisingly little. The results presented here give detailed insight into the interaction between the electronic states of organic adlayers and the silver surface.