Where are the LightRoom presets installed?
Under Windows XP they are located at C:\Documents and Settings\Your User\Application Data\Adobe\Lightroom\Develop Prests\WOW PhotoPresets.
Under Windows Vista they are located at Local Disk (C:)\Users\Your User\AppData\Roaming\Adobe\Lightroom\Develop Prests\WOW PhotoPresets.
Under Windows 7 they are located at C:\Users\(active user)\AppData\Roaming\Adobe\Lightroom\Develop Presets
NOTE: When running the installer, make sure you are running the installer as an administrator (right-click installer>run as administrator) in the user account you will be using
For Mac Users:
Mac HD/Users/User Account/Library/Application Support/Adobe/Lightroom/Develop Presets/WOW PhotoPresets