With cell phone numbers stored in mysql columns, I've found that by attaching an email trigger addressed to my cellphone carrier will dispatch a cellphone text message. (same concept for sending faxes, just a different address)
However there is a problem in that this only covers site users with the same cell phone carrier as mine.
How could I possibly identify who the user's cellphone carrier is aside from an outright request? (the only way -- another table col drop menu: "sprint" "nextel" + many independents)