The Firefly Mobile Phone for Kids is ideal to give parents access to their kids without having to give them a full mobile phone if kids are not old enough for them.

The kids mobile features 5 parent-programmable keys for up to 20 phone numbers. This phone lets parents control who their kids call and can limit minutes.
As the reviews on Amazon.com indicate the phone is ideal for young kids (5-7 years). Older kids you cannot convince anymore that this is the coolest phone in school.

Amazon.com sells the Firefly Kids Mobile phone for $99.99.
The Firefly does not have GPS, like for instance the i-Kids GPS locator. This would be the additional feature that would make this product much more valuable.