This paper presents the design of a lightweight framework to provide vertical handover for macro-mobility on handheld devices. The framework is designed for mobile-controlled handover and does not require modification of the Internet infrastructure. The framework enables users to control the entire vertical handover process so handover decisions are driven by user preferences rather than ISP considerations. UDP tunneling is used as the basis for seamless roaming. Support nodes participate in mobility management by keeping track of the mobile users. We elaborate on a proof-of-concept implementation targeted to be deployed on the Android platform.