Google allow users to send and receive email via SMS

Gmail users can now send and receive their emails via their feature phones.
However, this service will currently be available in Ghana, Nigeria and Kenya only but is likely to be launched in other regions later. It will help the search giant reach out to a larger audience in countries which do not have much mobile internet penetration.

According to  Google Africa's blog it says, "Gmail SMS automatically forwards your emails as SMS text messages to your phone and you can respond by replying directly to the SMS.Users can control the emails through commands like More, Pause and Resume.  They can create new mails via SMS and send the same to any email address. This email will be automatically placed in the correct conversation thread.
This feature require a feature phone with basic voice and SMS features in order to make full use of this service. Users can activate this service by modifying the settings in their Gmail accounts and registering their phone numbers with Google.