Unlimited experience and books:
Once you get to NCR( New California Republic ),go into the city. next go right one building and down unstill you see a female character and a robot just waiting outside of the building. 9 out of 10 times I ran past her she cries out for help. HELP HER! She brings you into the building that she was standing in front of. There will be a guy going to blow himself up, just let him blow up. Because of the explosion he damaged the regulator console for the power. Quickly repair it and talk to the lady she will give you some books and you get 3000 exp points.
Now you just repair it again and talk to the lady again and she will give you more books and you get 3000 exp points for "repairing the console". keep doing this to get unlimited exp points and books. I tried this and I never regretted it.

Armor Trick:
The problem with having companions like Sulik, Vic, Cassidy... is that they get killed for having a very low armor. But with this cheat, you don't have to worry about your companion. NOTE: this cheat only works on your buddies who can wear armor. Here's how it works: let's make sulik as an example, first, if you already have Sulik, let him wear any kind of armor. so sulik already have protection. for short, this trick is used to double, or triple... the effect of an armor wore. so Sulik already have an armor, then go back to communicating section (...where you talk to each other with his picture above.) then tell him to remove his armor. So that removes his armor into his inventory, the trick is that his armor was removed but the protection of that armor stays! so let him wear again his armor then that makes it double, the repeat this to make your comrade invulnerable! You don't have to worry about your buddies anymore... they can now take care of themselves! NOTE: !
the effect of the armor will be gone whenever your companions gain level. NOTE: the armor also duplicates armor class the armor have... well its a great thing but the only disadvantage is that whenever your companion (w/ duplicated protection) charges or attacks an enemy, that enemy will have nothing to do but runaway from you... its going to be a wild goose chase if you don't have ranged weapon!

Easy Stealing:
Steal one item at a time, especially those big guns & big armour. Save your game often.

Early Upgrades:
In Vault City, there is a store with a yellow smiley face. Ransack the store to receive guns, armours, ammo(s) and cash.

In New California Republic(NCR), just beside of the entrance there's a shop with a drawf, guarded by four green costume soldier. Steal Bozar from the soldiers and loot the store. Need a high stealing skills above 80%.

UNLIMITED OUTDOORSMAN SKILL:
Rescue Smiley the trapper. Talk to him, and after he's taught you to skin geckos, say "Can I ask you few questions about trapping geckos", and ask him to teach you, and when he
says that you need to learnmore than you know
you need to learn, say "teach me, oh great trapper". repeat this until you've got big
enough outdoorsman skill (or you get bored)

BEAT THE FINAL OPPONENT EASILY:
When you create a character, put endurance (EN) and luck (LK) to 6 or higher, and get a high speech skill. When you get your first three perks, (I mean perks at levels 3, 6 and
9) get three toughness. When you finally get to the President of the Enclave, stuff him full of super stimpaks, and wait him to die, and take his security key. When at the stage of the final showdown, use the security key on the computer terminal, and speak to the Enclave troopers, and convince them to join you. now that you've got lots of allies, and
advanced power armor mk II (You got it from the electrified floor puzzle room, right?), youll have 95% damage resistance, and you'll be able to beat him with bare hands (But you should still use your guns)

Faster Travel:
There's a person in Den who will sell his car to you if you got these parts.
(Fuel Cell Controller)Main part found in Geoko
(Fuel Cell Regulator)Faster travel, found in Klamath

Unlimited Money:
To get unlimited money all you have to do is have at least 200% gamblig skill and then go to somewhere with a casino and go to the craps tables. When you are asked how much you want to bet say the highest amount. If you do it a couple of times and you win, just keep clicking on the amount you want to bet and you will be able to get unlimited money.