Design
  Create Design Specifications (Diagrams, etc.) 24
Development
  ClientApp
    Connect to Server Dialog 16
    Create Channel Dialog 8
    Main Window
      Channels List 16
      Users List 24
      Chat Window 40
    Configuration 8
  ServerApp
    WCF Service 24
    Business Layer 8
    Configuration 8
QA
  Create Test Plan & Scripts 8
  Execute QA 32
UAT
  UAT Testing 80
Release to Production
  Prepare Setup Packages 16
  Create Deployment Instructions 8
  Implementation 8
  
Total: 328 hours
Design & Development: 176 hours. 2 offshore and 1 onsite resources. 
Offshore costs 30/hour, onsite 80/hour, average 46/hour. 
Cost of development: 176 * 46 = $8096