You can donate $10 to Haiti relief by texting “Haiti” to 90999.And yes, it's legit, and 1005 of the donations go to Red Cross relief efforts over there. According to the Red Cross's blog, they've received over $3 million as of this morning. They also have a map which breaks down giving by state.
For those who are always on the go, and may not have a checkbook or stamp handy, this is a great way to help. I applaud those who are involved with this effort, and my prayers are with the people of Haiti and those involved in the rescue effort.