16. The method of claim 14 , wherein the application state machine is a unified messaging system, and wherein the command is an enter command to enter a state within the unified messaging system.
16. The method of claim 14 , wherein the application state machine is a unified messaging system, and wherein the command is an enter command to enter a state within the unified messaging system. 17. The method of claim 16 , wherein the unified messaging system includes: a component that receives from a first device a message of a first format; and a unified messaging component that analyzes the message and converts the message to a second format that corresponds to a target device that conveys the message in accordance with a user instruction, the user instruction being transmitted via the currently selected user interface.