Official Post on Justice Points

You can read wowhead's post HERE.

Nethaera said: Although we’ve revealed some details of the conversion process, many of you have asked how many Justice and Valor Points bosses and daily dungeons will actually award. This list is incomplete, and the values may still change, but it covers the majority of the content we’ve been asked about.

Lich King Heroic dungeon boss -- 16 Justice Points
Lich King daily normal dungeon -- 12 Justice Points
Lich King daily Heroic dungeon -- 23 Justice Points
Lich King raid boss -- 23 Justice Points

Cataclysm Heroic dungeon boss -- 75 Justice Points
Cataclysm daily normal dungeon -- 75 Justice Points
Cataclysm daily Heroic dungeon -- 75 Valor Points
Cataclysm 10-player raid boss -- 75 Valor Points
Cataclysm 25-player raid boss -- 105 Valor Points

It’s important to note that once you outgrow content, by leveling past it by a predetermined amount, you’ll no longer gain points. The ‘outgrown’ level for end-game Wrath of the Lich King content is likely to be level 81. Once you level beyond Lich King content you’ll still be able to enter the dungeons, kill bosses, and see their drops, but they will not award you with points. This same principle applies to all content that provides Justice Points, including content from The Burning Crusade.