1. If you're in a flood prone area and your electricity has not been disconnected, inform Meralco to have it turned off ASAP to prevent possible electruction and other mishaps.
You can reach MERALCO here: Meralco (+63917-5592824).
In the meantime, shut off the main switch.
2. If you're fortunate enough to have been not been adversely affected and is in a position to help, coordinate with the local/nearby relief and rescue operations care of your Local Government Units (LGU), Church Groups, etc.
Clothes, blankets, and food are welcome.
3. Re-post information about emergency numbers (complete list here) in your blogs, plurks, tweeters, and other social network and encourage others to do the same.
Monitor the web and report about those still trapped to the proper authorities with the proper pertinent information (location, number of people, etc.).