A strong case can be made for grid computing using virtual machine monitors or virtual servers. In either case, the combination of a virtual machine's need for a network presence and the multi-site, multi-security-domain nature inherent in grid computing creates a challenging distributed network management problem. We have described and evaluated a tool, VNET, that addresses this problem by converting it into the familiar single-site network management problem. The combination of VNET and similar virtual network tools and virtual machines present an opportunity: adaptation and exploitation of resource reservations for existing, unmodified operating systems and applications. We described this opportunity in depth, pointing out specific adaptation problems and interactions with a specific resource reservation system. We are currently extending VNET to take advantage of this opportunity. VNET is publicly available and can be downloaded from https://plab.cs.northwestern.edu/Virtuoso.