If you've ever gone searching for these on the web, you know it's a royal pain. Here they all are in one convenient place.

Windows 7/Vista

Application Data
C:\Users\[USERNAME]\AppData\Roaming\[APP_ID]
ELS
C:\Users\[USERNAME]\AppData\Roaming\Adobe\AIR\ELS\[APP_ID]

OS X

Application Data
OSX/Users/[USERNAME]/Library/Preferences/[APP_ID]
ELS
OSX/Users/[USERNAME]/Library/Application Support/Adobe/AIR/ELS/[APP_ID]

Windows XP

Application Data
C:\Documents and Settings\[USERNAME]\Application Data\[APP_ID]
ELS
C:\Documents and Settings\[USERNAME]\Application Data\Adobe\AIR\ELS\[APP_ID]