I spent about 20 mins with ATT technical support today trying to figure out how to send a Text from their website.  Apparently they did some website updates and the “Send Text Message” option is buried.  Hope this saves you some time.

1. Go to https://www.wireless.att.com

2. Login

3. Click on Message Center under the Manage Tab

4. Click “Send Text Message”

5. Complete the form and click Send