Real Name: Eddie Brock
First Appearance: Well, that depends on which part of Eddie you're talking about. Eddie's costume is actually a living organism that has merged with Eddie after serveral attempts to bond with Spider-Man. It originally showed up during the Secret Wars miniseries. Eddie was first seen during cameos in Web of Spider-man #18 and Amazing Spider-Man #298-299, but issue #300 was his first full appearance and therefore the one that costs big bucks in comic book stores.
What's His Problem?: Eddie was a reporter who did a series of interviews with the vigilante known as the Sin Eater, during which Brock, under pressure from the authorities, revealed the name of the Sin-Eater himself. Unfortuanatly, Eddie didn't check his sources carefully enough to find out his pal was a wacko who thought he was the Sin-eater, not the wacko who was the Sin-Eater. This mistake got him fired for sloppy journalism. Sinse Spider-Man was the one who uncovered the identity of the real Sin-Eater, Brock blamed the Web-Slinger for his journalistic disgrace. Forced to write for sleeze magazines because no respectable publication would touch him, Eddie was in church contemplating suicide when the symbiont, weakended from a recent battle with Spider-Man and attracted by the force of Brock's despair, found him. When they bonded, the symbiont became overwhelmed by Eddie's dislike for its former host, and Eddie learned all of Spider-Man's secrets. The bonding does not seem to have improved the emotional stability of either the symbiont or Eddie.
Heroes He Keeps Running Into: Venom has become one of the most popular bad guys in the Marvel Universe, which keeps him pretty busy. Although he will always be associated with Spider-Man, he has fought the Black Cat, Darkhawk, memebers of the Fantastic Four, Ghost Rider, the Punisher, and Silver Sable(to name but a few). In addition to a buncha good guys, Venom has a long running fued with his offspring Carnage.
People Who Think He's Not So Bad: All things considered, Eddie's ex-wife Ann tolerates him pretty well. Venom is also well thought of by the homeless of San Francisco, whom he has periodically championed.
Most Despicable Act: Although his code of honor prevents him from murdering innocents, his definition of innocence is a little loose. He once tricked and then killed a prison guard who was only doing his job, which always struck me as both low and hypocritical.