The Red Cross has set up shelters in various communities. You can donate to the Red Cross Disaster Relief fund here, and the organization also suggests giving blood at your local hospital or blood bank.
If you're searching for a missing relative, check Red Cross Safe & Well's site. And please register if you're within the disaster region. The site is designed to make communication easier after a tragedy like this.
If you want to send a $10 donation to the American Red Cross Disaster Relief fund via text message, you can do so by texting the word REDCROSS to 90999. The short code to donate to the Salvation Army tornado relief in Oklahoma is STORM to 80888. As in the case with other donations via mobile, the donation will show up on your wireless bill, or be deducted from your balance if you have a prepaid phone. You need to be 18 or older, or have parental permission, to donate this way. (If you change your mind, text the word STOP to 90999.)
Phone: 1-800-RED CROSS (1-800-733-2767); for Spanish speakers, 1-800-257-7575; for TDD, 1-800-220-4095.
HD Footage of the tornado tearing through Oklahoma:
This video captures the birth of the deadly tornado:
Watch as this woman finds her dog under rubble left by the storm: