Jabba in Life: Jabba the Hutt, as his name would suggest, is a Hutt. The Hutts are a species of alien in the Star Wars universe, who look pretty much like giant slugs, and are extremely well known for criminal activity and ruthlessness. As for Jabba the Hutt, if the Hutts are the gangsters of the galaxy, he's the Al Capone of the bunch, with a thriving criminal empire based on the desert world of Tatooine.
Jabba's Vengeance: Jabba the Hutt has something of a history with Han Solo, who used to fly as a smuggler for Jabba. One time, Han was smuggling a large consignment of spice from Kessel when he was stopped by an imperial patrol. In order to save himself from capture, he was forced to jettison his expensive cargo into space. Of course, being the vengeful Hutt he is, Jabba was none too pleased about this and demanded reparations from Han. When Han was unable to pay the demanded amount, Jabba put a contract out on his head.
As anyone who has seen the movies knows, Boba Fett with the assistance of Darth Vader captured and froze Han Solo in carbonite. Han was then delivered to Jabba, who kept him frozen as a trophy on his wall.
Jabba's Death: Following an unsuccesful attempt to break Han Solo free from Jabba's palace, Jabba captured and sentenced Luke Skywalker, Chewbacca and Han Solo to death by being flung into the Pit of Carkoon, the resting place of the almighty Sarlacc, while ordering that Princess Leia become his new dancing girl.
However, not all went to plan, for those sentenced to death made a daring escape moments before their execution, overpowering their guards. In the confusion, Princess Leia managed to strangle Jabba using the very chain which was intended to prevent her escape. Finally, before escaping Jabba's yacht, the escapees turned the craft's deck gun upon itself, creating a chain of explosions, destroying the yacht and Jabba's body with it.