Hi guys,
There is a nice free online SF4 tournament with prizes over at ReflexGT.com:
Street Fighter IV (Xbox 360) 1v1
1st: XBL 2100 MS Points
2nd: XBL 800 MS Points
There are more tournaments for the ones interested:
Btw, prizes are sponsored by the organizers (gamers) themselfs. They did it cause the thought there was a lack of free online tournaments with prizes on the interwebz...
Good luck guys.