The basic circuit switched data for GSM is 9,6 kbit/s. With High Speed Circuit Switched Data (HSCSD) bit rate can be up to 57,6 kbit/s. GPRS bit rates can vary e.g. 20 - 50 kbit/s. For example Multimedia Messaging Service (MMS) is using GPRS as bearer.
The provided bit rates vary depending on the operator so please contact your own operator for exact information.