During the past decade, computer simulations of bilayers have moved from the realm of model systems to realistic systems containing tens of phospholipids along with the requisite number of water molecules hydrating the entire molecular assembly. Concomitant with the ability to model larger and larger systems, simulators have also begun to utilize more accurate numerical tools to ensure that the temperature, pressure, simulation timescales, parameter sets, and long-range electrostatic interactions of bilayers are correctly accounted for in a typical molecular dynamics simulation. With these tools in hand, work has already begun to define the structure, function and dynamics of bilayer, bilayer/small molecule and bilayer/protein systems. Thus, we have reached an era in which simulators will tackle more and more detailed issues regarding complex bilayer systems.