With rapid advancement of 3G wireless network technology, mobile Internet access is becoming more and more popular in recent years, and web access by mobile phones even surpassed that by other means. Users' level of satisfaction of services based on such rapidly developing technology immediately becomes an important issue. The distributed QoS (Quality of Service) / QoE (Quality of Experience) measurement platform proposed here solves this problem by offering network engineers capability to monitor network service quality and the likely QoE as experienced by phone users while watching streaming videos, for purposes like benchmarking and tracking down problematic cells. There are three major components of the proposed system: (1) client program; (2) backend server; and (3) web interface. The client program runs on Android smartphones. Using the various equipped hardware sensors, radio information, location information and network statistics, etc., are collected. By exploiting the mobility of smartphones, data can be collected wherever the phone is located. Those data are uploaded to the backend server for data aggregation and processing. In particular, a QoE computation algorithm recommended by ITU is used to convert raw data into QoE scores. To facilitate easy access to the general network service quality, a versatile web interface is also implemented to give detailed information of individual data collection sessions.