In Goodsprings Cemetery. On the second grave to the west of the Courier's (open) grave, at the northern edge of the cemetery (near the water tower). The grave is the only one in the area with rubble on top; the snow globe can be found among it, in front of the marker.
In the cocktail lounge of the Lucky 38 Casino. The snow globe is on the counter "behind" the middle cash register with a green lamp next to it (you must first speak with Mr. House to gain access to this area).
Located near Dean's Secret Stash in the upper levels of Salida del Sol North. From the southern-most entrance to Salida del Sol South (inside a house in Salida del Sol North), proceed down the stairway and out to the street, then look behind you for the entrance hole in the wall above. This area can be reached by going up the stairs located around the corner to the southeast and following the rooftops back toward the hole.