OK, most of the information is already there so I'll just do a little about his death.
St. George was a Roman soldier, who was also martyred by the Romans in about AD 350. During the Middle Ages stories appeared telling how he rescued a king's daughter from a dragon (Which is where the stereotypical damsel in distress comes from). He became the patron saint of England and of Spain as well.
The thing that most people don't know is how he died, its pretty disgusting though. First he was hanged, not until death though. Then he was nailed to an oaken table and crucified. Following this he was boiled in lead and then decapitated. The Romans did this because he was a Christian.
England has since adopted his flag, a red cross against a white field as their countries flag.