Wireless Local Area Networks (WLANs) have become omnipresent: WLANs are available at airports, coffee shops, university campuses, corporate environments, and homes. This surge in the popularity of WLANs motivates the study of how these networks are used. Characterizing WLANs, however, is complicated by a number of factors including the geographic diversity of WLAN deployments and the need for capturing activity in the wireless environment instead of the wired environment. In this paper, we describe our experiences with the deployment and use of a remote passive wireless-side measurement infrastructure for monitoring usage of WLANs, and compare our results with a commonly used wired-side measurement technique.