1. A method for selecting a method of execution for an application program, the method comprising: (a) receiving credentials; (b) enumerating a plurality of applications available to a client machine responsive to the received credentials; (c) receiving a request to execute an enumerated application; and (d) selecting one of a predetermined number of methods for executing the requested application, responsive to a policy, the predetermined number of methods including a method for executing the requested application in a computing environment provided by a virtual machine.