Here are some ways you can help.
CBS42 has a list of ways to donate water, non-perishable food items, clothing, etc., for people who are within driving distance.
AL.com has more ways for people who are in the region to help.
If you want to volunteer, call the United Way at 211.
alephz took the time to put together a list of ways to donate money. I'm c/ping that here.
You can donate to the Alabama Red Cross. Or even the regular Red Cross. There's also the Salvation Army and the Alabama Governer's Emergency Relief Fund
There is also a link to many ways you can help here:
Stuff to send to Alabama.
A couple things you should know: They are looking most for money, bottled water, and non-perishable food items, flashlights, batteries, hand sanitizer, as well as gift cards to stores like Wal-Mart, Lowes, and other big chain stores that are located in the area.
Anyone who sends me confirmation of a donation of $10 or more (you can send me a photo of a text confirmation if you do the text to the Red Cross or Salvation Army thing) will get a black and white drawing of a single figure (person, animal or thing). If you send $50 or more, I will draw 2-3 figures for you. You could have a usericon like my usericon, for only $10!