The Particle Beam Optics Interactive Computer Laboratory (PBO Lab) is a new software concept to aid both students and professionals in modeling charged particle beams and particle beam optical systems. The PBO Lab has been designed to run on several computer platforms and includes four key elements: (1) a graphic user interface shell, (2) a graphic beamline construction kit for users to interactively and visually construct optical beam lines, (3) a knowledge database on electric and magnetic optics elements, including interactive tutorials on the physics of charged particle optics and on the technology used in particle optics hardware, and (4) a set of charged particle optics computational engines that computes transport matrices, beam envelopes and trajectories, fits parameters to optical constraints, and carries out similar calculations for the graphically-defined beam lines. The primary computational engines in the first generation PBO Lab are the third-order TRANSPORT code, the multiple ray tracing program TURTLE, and a new first-order matrix code that includes an envelope space charge model with support for calculating single trajectories in the presence of the beam space charge. Progress on the PBO Lab development is described and illustrations from the Windows 95 implementation are presented.