Here is the link to Red Cross web page with specific information about how to donate by sending a text message. What you do is send a text message “Haiti” to the number 90999. There is no confirmation when you send the text, at least I did not get any confirmation. Update: The confirmation came in late. I had to reply “YES” to a message. Once you send “YES”, you get another message thanking you and informing you that $10 will be applied to your monthly bill. DON’T panic when you get another message asking you to send “YES” again. This is not for the money. This is to get ~4 messages per month from Red Cross about the relief.
This article says Canadians can also donate similarly.
You can also text “Yele” to 501501 according to the Yele page here.
Better business bureau has an article on what you should know when donating money to Haiti relief. You can find the article here.
Attorney General has issued a warning about scams.
Here is another piece from NPR about FBI warning on the scams.