Flash SMS messages or privileged Class '0' text-messages is a special type of message which appears directly onto phone's screen bypassing the usual 'Inbox' route, this type of messages are often used by mobile operators to display information on user screens grabbing immediate attention. The good thing is there are free software's availble to utilize this for all major mobile platforms like Symbian, Android and iPhone, today we will be reviewing one such free utility for Apple iPhone. Free Cydia app. "Flash SMS" as the name suggest allows iPhone users to send Flash SMS Text messages which displays directly onto receivers phone screen.