in case you don't know yet, the 4 new maps are schedualed for release Monday April 25.
the guys at Red vs blue have put together walkthroughs of the new maps-
currently there's only
Containment:
http://www.redvsblue.com/archive/download.php/?id=638
and
Warlock:
http://www.redvsblue.com/archive/download.php/?id=635
Sanctuary should be released soon (I've already seen the vid), and Turf shortly thereafter
www.redvsblue.com