3GPP is currently in the process of standardising the Multimedia Broadcast / Multicast Service (MBMS). In this paper the technical solutions adopted for the provision of these services over the GERAN A/Gb mode are presented. Simulation results are provided showing the data rates that can be achieved over the radio interface using the data transfer mechanisms already available in Release 5. Some of the concepts (to be included as part of Release 6) that have been proposed in 3GPP to increase the data rates, such as outer coding in the RLC layer or point-to-multipoint (p-t-m) with feedback, are also discussed, and their performance gain demonstrated through simulations.