Android 4.0, code named Ice Cream Sandwich, is the fourth major release of the Android operating system. It combines the previous tablet (3.0) and phone (2.3) codelines into one — Android 4.0 is designed to work with both tablets and phones.
Only use this tag when your question is truly specific to Ice Cream Sandwich. For example, it's appropriate to use when asking about an ICS feature, but not when asking about a device hardware issue unaffected by the OS (even you're using ICS on that device!).
Don't ask when your device will be updated to ICS or if it supports ICS; refer to this question instead!