There are 20 bobbleheads scattered throughout D.C., one for each skill and stat. The skill bobbleheads net you +10 to the respective skill, while (correct me if I'm wrong) the stat bobbleheads grant you a +1 to the particular stat, meaning that if you want to make the most out of the points offered in the game, do not level a skill above 90 or a stat above 9 unless you've already collected the bobblehead governing it.
This guide as found at Planetfallout.com with the "Unarmed" competed:
Strength - Megaton - Lucas Simms House
Perception - Republic of Dave - Museum of Dave
Endurance - Deathclaw Sanctuary - Deathclaw Sanctuary Entrance
Charisma - Vault 108 - Cloning Lab
Intelligence - Rivet city - Science Lab
Agility - Greener Pastures Disposal - Office
Luck - Arlington Cemetery North - Arlington House
Barter - Evergreen Mills - Market Bazaar
Big Guns - Fort Constantine - CO Quarters
Energy Weapons - Ravenhold
Explosives - WKML Broadcast Station - Sealed Cistern
Lockpick - Bethesda - Bethesda Offices East
Medicine - Vault 101 - Dad's Desk
Melee Weapons - Dunwich Building - Virulent Underchambers
Repair - Aerefu - Evan Kings House
Science - Vault 106 - Living Quarters
Small Guns - National Guard Depot - National Guard Armory
Sneak - Yao Guai Tunnels - Yao Guai Den
Speech - Paradise Falls - Euology's pad
Unarmed – Rockopolis – Head directly west from Casey Smith's Garage, look for tattered banners strung up. Use your local map or you may miss it.
And this one's from the fellas at Xbox360achievements.org:
Vault 101 - On Your Dad's Desk when leaving
The Republic of Dave - On bookshelf in Museum of Dave on the right.
Paradise Falls - Inside the Slave Masters house(Euology's pad) On a table.
Rivet City - On Dr. Li's table in science lab
Evergreen Mills - Market Bazaar in the back - on a shelf in the upper right hand side behind the Raider Trader that doesn't attack you.
Vault 106 - In the living quarters second level main room. On a table in middle of room.
Deathclaw Sanctuary - right at the beginning on a table next to a rotting Brahmin corpse.
Yao Guai Tunnels - In the Den, on top of a metal box on the right side of your map near some water.
Megaton - In Sheriff Lucas' house. - posted by Rubiq
Arefu - Inside the Sheriff's house. - posted by Sms4001
Bethesda Ruins - Inside the East Bethesda building, top floor near the door to the bridge. - posted by Shadow83
Dunwich Building - Inside the Virulent Underchambers, right before you leave the chambers on the floor right beside the door. - posted by Strygrog
Vault 108 - Cloning Labs - posted by Necromancer2k8
Fort Constantine - C.O. House - In the basement. In a safe in the wall. - posted by Necromancer2k8
Greener Pastures Disposal - In a small office covered in Radiation - posted by rubiq
National Guard Depot - In the Armory, you must first go through the Training room and Offices, you'll come out of a door in the main room, hit the power switch on the wall to your left and then you can get into the Armory door. It is on a shelf in the Armory. -
posted by Tylerko
Arlington National Cemetery - house to the north bobblehead is in the basement on a shelf directly below the stairs. posted by moosey82
Raven Rock - Must get on your first run through here, you cannot go back. Arlington National Cemetery, house to the north bobblehead is in the basement on a shelf directly below the stairs. - posted by Sms4001
WKLM Broadcast Station - go to the WKLM Broadcast station, face south and drop off the small cliff, then turn to your right, its somewhere along there.
Its a tiny manhole cover thing and it is quite hard to spot as its tucked away.
it also helps making your way to about half way towards Faded Pomp Estates, then turning facing North, then go dead on North.
*edit* go to the WKLM and turn on your local map, it should show a doorway to sealed cistern....... I always forget about the local map - posted by Srippa
oh, and please sticky if you find this helpful.
gold star for you:D
gamer tag: xATTICUSx561x
bump, sticky, or tag if you plan on using this please, otherwise we're going to be seeing a lot of bobblehead questions overwhelming the board.
wow this should be stickied
bump - sticky!
Ubiquitous Master of the AMA