My aunt has an iPhone 4 with the latest operating system and cannot imessage. How do we activate this? Her menu selection under settings is different from mine. She does not have the option to turn on imessage.
Perhaps she is using an iPhone 3G and her "latest operating system" is 4.2.1 (the highest it will run). You need iOS 5 or higher to have iMessage. Have her check Settings>General>About and tell you the number next to Version.