The 8 Ball is a random loot item from the Enforcer tier. You have a small chance of getting it from any job in that tier.
You can get all the billiard balls by doing jobs in the Enforcer Job Tier of Mafia Wars.
At the enforcer level do rob an electronics store
I received the Eight Ball on the Federal Reserve Raid job in the Enforcer Tier Level 1. Have not found the cue ball yet, any clue where it is?
In Street Thug Job Mafia Wars New York, by doing the job, or you can ask your friend to give it.
You can receive the three ball by doing jobs under the Enforcer job tier or you can get one of your mafia to gift to you.
No such item exists in mafia wars
You get the German ball from drops whilst doing the global cup challenge, or you can get one sent by a mafia member if you add it to your wishlist.
When they go to war their 6 top mafia is displayed. these are the ones that have to be killed to win the war.
When they go to war have a look at their top mafia.
Click on their profile under "My Mafia" on the "Mafia" page, and hit declare war. It should be the first option from your right under their profile info.
Cue ball is part of the Billiard ball collection in New York.
The only way to get the Two Ball in Mafia Wars is by doing jobs in the Enforcer Tier, the only other option is to have a friend gift you one.