Here’s how you setup an Out of Office reply in your Google Apps email hosting:

  1. Login to your webmail (either goto mail.youdomain.com or http://mail.google.com) 
  2. Click on the wheel/cog in the right hand corner of the screen and go to Settings
  3. Click the ‘General’ tab on the new screen that appears.
  4. Scroll down to the Out of Office reply section
  5. Complete the fields as you need to, enter a reply message as you need to.
  6. Once you’re happy with the setup go to the bottom of the page and click ‘Save Changes’ and you’re done!