Performance of wireless data networks can be improved by integrating heterogeneous networks. Hence, emerging wireless Internet networks consist of heterogeneous wireless networks working in synergy. WiFi and WiMAX are particularly interesting in their ability towards mobile data oriented networking, and a scheme that enables mobility across these two would provide several advantages to end-users, wireless operators as well as Wireless Internet Service Providers (WISPs). In this work, we propose a novel, cost-effective and end-user friendly mobility scheme. Our approach does not require additional client software to handle WiFi-WiMAX mobility, or hardware changes in any of the network entities involved. We demonstrate the feasibility of our solution by developing an actual prototype.