Remote dual boot, how to select OS to boot
You can use BootChamp to quickly restart in Windows from OS X. To restart in OS X from Windows see OS X Lion - Start up using Mac OS X or Windows:


  Restart directly in Mac OS X from Windows:
  
  Click the Boot Camp icon in the system tray and choose “Restart in Mac OS X.”




A more tedious way is to set the startup disk to the other OS every time and then restart. From the OS X Lion - Start up using Mac OS X or Windows page linked above:


  Set the default operating system:
  
  
  Do one of the following:
  
  
  In Mac OS X, choose Apple > System Preferences and click Startup Disk.
  In Windows, choose Boot Camp Control Panel from the Boot Camp system tray item.
  
  Select the startup disk with the operating system you want to use by default.
  If you want to start up that operating system now, click Restart.
  


The Apple support page for OS X Mountain Lion - Start up using Mac OS X or Windows contains the same instructions for OS X Mountain Lion.