P2P IPTV systems start to be very popular on the Internet. Measuring the impact they have on the network and understanding their behavior is an important field. Available applications are based on proprietary solutions, thus traffic analysis is the only feasible way to identify the mechanisms used to get video streams. In this context, during the 2006 FIFA World Cup, we performed an extensive measurement campaign. During this worldwide event, we measured network traffic generated by the most common P2P IPTV applications, namely PPLive, PPStream, SOPCast, an TVAnts. Our observations show that all these applications generate different traffic patterns and use different underlying mechanisms. Each application has its own download policy and maintains a different set of peers. From the traces we collected, we extract several statistics, which help in having a better understanding of the behavior of P2P IPTV systems.