If your cell phone provider is not listed, you can also subscribe by using your phone's SMS email address.

Almost every carrier allows text messages to be send by email using an email address similar to 1234567890@mycarrier.com

To find your phone's email address:
1) Send a text message to your regular email address.
2) When you get the email, look at the "from" address.
3) Use that "from" email address to subscribe to the alerts you want to receive.