Previously slated for release May 7, New Super Mario Bros. has been quietly pushed to May 15 on Nintendo's release calendar.
Astute observers will note that May 15 is a Monday, and as such is in-line with Nintendo of America's Monday game ship tradition, as opposed to the earlier commitment of May 7 — as a Sunday, it fueled speculation that the DS Lite would be releasing to North America at the same time. Current wisdom holds that Nintendo wants to satisfy the frothing demand for the Lite in Japan and ramp up manufacturing capacity before trying to bring the handheld over here.