Resource-constrained embedded and mobile devices are becoming increasingly common. Cyber foraging, which allows such devices to offload computation to less resource-constrained surrogate machines, enables new and interesting applications for these devices. In this paper we describe a surrogate infrastructure based on virtual machine technology that allows resource-constrainted devices to utilize a surrogate?s compute, network, and storage resources. After describing the design of our surrogate infrastructure, we demonstrate how it can be used to support real-time speech recognition and a synthetic web services application. Using a surrogate reduces the response time of speech recognition by a factor of 200 while reducing the energy drain on the client device by a factor of 60. Using a surrogate reduces the response time and energy drain on the client by factors of 21 and 25, respectively, for the web services application.