Optical wireless LANs have the potential to provide bandwidths far in excess of those available with current or planned RF networks. There are several approaches to implementing optical wireless systems, but these usually involve the integration of optical, optoelectronic, and electrical components in order to create transceivers. Such systems are necessarily complex, and the widespread use of optical wireless is likely to be dependent on the ability to fabricate the required transceiver components at low cost. A number of U.K. universities are currently involved in a project to demonstrate integrated optical wireless subsystems that can provide line-of-sight in-building communications at 155 Mb/s and above. The system uses two-dimensional arrays of novel microcavity LED emitters and arrays of detectors integrated with custom CMOS integrated circuits to implement tracking transceiver components. In this article we set out the basic approaches that can be used for in-building optical wireless communication and argue the need for an integrated and scalable approach to the fabrication of transceivers. Our work aimed at implementing these components, including experimental results and potential future directions, is then discussed.