Where are the Explosives and Lockpick bobble heads in fallout 3

The Explosives Bobblehead is within the Sealed Cistern at the WKML Broadcast Station. If the map was split down the middle vertically and horizontally, WKML will be almost dead centre of the north western quadrant.

The Lockpick Bobblehead is located at Bethesda Ruins, Offices East. Enter the Offices West building and proceed through it until you cross a walkway into the east building as you may not be able to access the Bobblehead entering the east building. To find Bethesda Ruins, walk a few miles north of the Super Duper Mart (or you can follow the main highway leading north from Vault 101 where it eventually bends to the east).