After a few false starts overnight AT&T finally got the Unlimited Mobile to any Mobile feature listed and functional in their account management site.
To get this free feature added to your account visit www.att.com/anymobile. As soon as you login you will be taken directly to the features option for your phone plan.
You will be presented with a list of available text messaging options. You want to choose the one that has Unlimited With Mobile To Any Mobile Calling If you are on a family share plan unlimited messaging is $30 and $20 for individual plan.
Once you choose your plan and hit next you will be asked when you would like this new feature to be effective. You can choose the start of the billing cycle, today or next cycle. I simply chose today as it really did not matter in my situation.
After pressing next and reviewing the terms and conditions, click Submit and you are done. Now get on that phone and start making your unlimited mobile to any mobile calling.
If you have any questions or issues simply call AT&T customer care at 611 from your mobile device.