Sadly another problem with Discovery led to STS-119 being delayed. A Gas Leak was the problem - Corgi Fitter to the Launch Pad...
Try again Sunday - maybe?
Full story at SPACE.com -- Gas Leak Delays Space Shuttle Launch - http://www.space.com/missionlaunches/090311-sts119-launch-scrub.html
Picture of the offending Vent Line here at he NASA Space Shuttle Blog - http://www.nasa.gov/mission_pages/shuttle/main/index.html