After the 90 minute power outage yesterday, Marietta suggested posting the link for Center Point's notification service. Not only can you view real-time outages on this site:
http://centerpointenergy.com/OutageTracker

You can also get text messages from them about estimated restoration times. I received these:

"We are aware of a power issue at or near GREEN MEADOWS LN.. affecting 3720 customers. Estimated repair completion by 1:45 PM - actual time may vary."

"Repair estimate update: Our crews now estimate that our work will be complete by 2:46 PM. Thank you for your patience."

Sign up here:
http://centerpointelectric.com/PowerAlertService