The planet Naboo is one of the "jewels" of the Star Wars universe. The planet itself is very beautiful and it is known for the very sleek starships built there.
It is home to two peoples, the human Naboo and the Gungans, an amphibious species believed to be native to the planet. It was also the home of several notable politicians, namely Padme Amidala, Jar Jar Binks (although that one is disputed strongly by Star Wars fans, he was enough of a politician to be able to move to give emergency powers to the Supreme Chancellor), and Palpatine, who went on to become the Supreme Chancellor of the Republic and the Emperor of the Galactic Empire.
Naboo became the site of the first major conflict within the Republic for almost a millennium when it was blockaded, and later invaded, by the Trade Federation during the events of Star Wars: The Phantom Menace. It was also the first time the any Jedi had to face off against a Sith (namely Darth Maul) in about as long, and also was the first time that a large group of the Battle Droids that became the backbone of the Seperatist Army during the Clone Wars saw action. Naboo was also where Jedi Anakin Skywalker and senator Padme Amidala were married.
Naboo is where a large majority of the film The Phantom Menace takes place, and it is seen again in Attack of the Clones and Revenge of the Sith. When the original trilogy of Star Wars films were released for the first time on DVD, a slightly extended ending was added at the end of Return of the Jedi where a glimpse of Naboo is seen.