The Hulk has landed. He's in Manhattan, causing Mayhem.
Meanwhile, Amadeus Cho has assembled some renegade friends of Hulk, including Hercules, Angel and Namora. All have their own reasons to support the Green Goliath.
Cho and the Renegades try to talk to the Hulk. The Hulk beats, threatens, intimidates and generally treats them badly, repeatedly claiming to be a killer. But Cho and his friends refuse to abandon The Hulk, Cho keeps insisting that the Hulk is essentially good. He claims that the Hulk has never killed except in absolute self-defense, or when his mind wasn't his own.
In-between this running ethical debate, the Hulk is attacked by the army with Adamantium shrapnel (it hurts him but doesn't do anything permanent), Cho and his friends are attacked with missiles (they fight them off), Rick Jones turns up and has a crisis of love/hate vs. the Hulk, and SHIELD conscripts Cho to help minimise civilian damage and casualties.
The Hulk builds a battle arena, and Cho goes to investigate, accompanied by the new female Scorpion (an agent of SHIELD). Cho sees that The Hulk has imprisons The Fantastic Four and The Avengers, including Spider-Man. See World War Hulk for the main story of this.
Spider-Man's involvement is a one panel cameo chained silent and motionless to a pillar in the basement of the battle arena. Like all the other heroes, he is wearing his "obedience disk".
Personally, I think World War Hulk was too big. Spread over thirty-something issues, it's just bloated so that Marvel can wring as much cash from it as possible. That's the nature of these things. One upon a time we thought a twelve issue "Secret Wars" was unnecessarily large. Now we get crossovers like Civil War that span a dozen titles, with fifty issues (or eighty if you include variant covers).
Still, Amadeus is an interesting character, and this is a nice counter-point to the main events of World War Hulk.
The Incredible Hulk shows how Spider-Man could be written. Concentrate on stories and characters, work with the character as you find it, and don't spend all your time worrying about what should be ret-conned.
Three and a half webs for a story that just gets on with telling stories.