I guess it depends on your time zone, eh?
According to
http://dawnsun.net/astro/moon/, the January Full Moon becomes full on 30 January 2010, 06:19 GMT. My time zone is PST, which is GMT -8 hours, so here the moon becomes full 29 January 2010, 10:19 PST.
What sources did you check, what TZ did you use, and what math did you do? Indeed, it becomes full at 1:19 AM EST 30 Jan 2010, and 12:19 AM CST 30 Jan 2010, but 11:19 MST 29 Jan 2010, and, as noted, 10:19 PM PST...
And then there's AK and HI...