1) Where can I buy 4.7mm caseless ammo?
2) Is there any armor better than Advanced Power Armor?
3) Who has the most gold for bartering?
4) I can no longer do slaving work at the Den What happened? And where do I go for a new slaving job? (Note: I'm already in a gang, one without slave buisness)
5) Where can I find a P90 and a Gauss Rifle?
6) How do I "dual wield"? I heard I could dual wield P90s...

1) Where can I buy 4.7mm caseless ammo?
That ammo is like hens Teeth, occasionaly San Fran... But theres no regular supplier I can think of
2) Is there any armor better than Advanced Power Armor?
Avanced Power Armour MK2 - But its only on the oil rig.
3) Who has the most gold for bartering?
The San Fran Merchants, and the Cashier at the Redding Casino
4) I can no longer do slaving work at the Den What happened? And where do I go for a new slaving job? (Note: I'm already in a gang, one without slave buisness)
Nowhere really. You can do some work for a slaver in NCR, but its not slaving work.
5) Where can I find a P90 and a Gauss Rifle?
Dunno about the P90 (dont even remember it being in game), but you can get a Guass rifle in Navaro
6) How do I "dual wield"? I heard I could dual wield P90s...
You heard wrong. There is no Dual Wield.

Thanks. New one: Where can I find an ally or two? Or three? By the way, I'm evil. Like child killing evil.

So can anyone tell me where to find some allies in Fallout 2?

Sulik: Good, non slavers only, Klamath, just buy his debt
Vic: Anyone, The Den, Just get his radio from klamath and buy his debt
Cassidy: Non Slavers only, Vault City, just ask him to join
The Slaughterman's Kids: Anyone, Just, erm, have him walk in on you and the kid in question (Worthless)
Myron: Anyone, Stables by reno: Just talk yourself in, and ask him (almost Worthless)
Marcus: Good only, Do some quests around Broken hill and he will let you.
Skynet: Get all the parts required to build him (better science for a better companion) in Sierra Military Depot
K-9 - Do some work for a exiled Enclave scientist in NCR
Cyberdog - Kill his master and fix him in Navarao