There is an increasing need to build scalable distributed systems over the Internet infrastructure.However,the development of distributed scalable applications suffers from lack of a wide accepted virtual computing environment.Users have to take great efforts on the management and sharing of the involved resources over Internet,whose characteristics are intrinsic growth,autonomy and diversity.To deal with this challenge,Internet-based Virtual Computing Environment (iVCE) is proposed and developed to serve as a platform for distributed scalable applications over the open infrastructure,whose kernel mechanisms are on-demand aggregation and autonomic collaboration of resources.In this paper,we present a programming language for iVCE named Owlet.Owlet conforms with the conceptual model of iVCE,and exposes the iVCE to application developers.As an interaction language based on peer-to-peer content-based publish/subscribe scheme,Owlet abstracts the Internet as an environment for the roles to interact,and uses roles to build a relatively stable view of resources for the on-demand resource aggregation.It provides language constructs to use 1) distributed event driven rules to describe interaction protocols among different roles,2) conversations to correlate events and rules into a common context,and 3) resource pooling to do fault tolerance and load balancing among networked nodes.We have implemented an Owlet compiler and its runtime environment according to the architecture of iVCE,and built several Owlet applications,including a peer-to-peer file sharing application.Experimental results show that,with iVCE,the separation of resource aggregation logic and business logic significantly eases the process of building scalable distributed applications.