Here is how you access this feature:
1. Go to https://www.att.com/olam/dashboardAction.olamexecute
2. Login with your Wireless Phone number and password.
3. Click Account Overview.
4. In the right column, under Quick Links, click Manage My A-List.
5. Follow the screen prompts to Add the Numbers to your list.
6. In my case, under My Account, I clicked on Usage and Current Activity for my phone(s). I sorted the phone listing by Minutes, added Contacts for the Non-AT&T mobile numbers/landlines that I thought would be used the most in the future.
7. To monitor the usage, I also downloaded the AT&T iPhone App.
This was not a highly advertised new AT&T feature, but is now available for selected plans. In other words, if you get an AT&T iPhone bill that drained your rollover minutes, this will be the feature recommended by AT&T.
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Click for More info on AT&T A-List Wireless Phone Savings