This is from Marvel Zombies Return #1, by Fred Van Lente and Nick Dragotta.
Zombie Spider-Man finds himself in an alternate dimension resembling the past (specifically, Amazing Spider-Man #68). He reads about the tablet Kingpin and Silvermane are after, which can reveal the key to eternal youth. Spidey thinks that if he finds the tablet, he may be able to cure himself of his his zombism. He also sees Gwen, MJ, Harry, and his younger self.
When the Sinister Six attack, the normal Peter runs off to change and Zombie Spider-Man swings in to save the day.
Then he fights the Kingpin, who is trying to steal the tablet.
Sandman, who had managed to escape, runs into the normal Spider-Man and kills him. Meanwhile, the Zombie Spider-Man is horrified to discover that the other members of the Sinister Six who he killed have turned into zombies themselves and eaten his loved ones.