Update: 23rd Oct 09:45 Thanks to Ryan for these extra photos.
You can see more at his Flickr Site here.
Update: 23rd Oct 08:30 Thanks to Odul
BeckStabber: Just heard from sis: the building that Jack ran up to in the filming today was transformed into a school called Saint Mary's Academy #Lost 2 minutes ago from web
Thanks to The ODI and to Odul for the heads up. Nothing very spoilery but we'll add more if/when we get more photos etc.
Sources
http://twitter.com/ChunteeDrea
http://twitter.com/BeckStabber