The main planet in this episode, Naboo, was originally called Utapau. This planet name was also considered for episode IV, and was eventually used in episode III as the planet where General Grievous and Obi-Wan Kenobi have their showdown.
This was the most expensive of the Star Wars movies to make, with an estimated budget of over $120 million.
All of the Clone Troopers in this movie are CGI, and not a single Clone Trooper costume was physically made for this movie.
The plot for this, the first Star Wars movie, was finished by George Lucas in 1975.
Harrison Ford originally asked George Lucas to kill off Han Solo in this episode, believing the role of Han Solo had played out. This was a consideration, and left open-ended as Han Solo was frozen in cabonite and left in this state at the end of the film.
George Lucas used the code name "Blue Harvest" for this film, claiming it was a horror film while shooting in Yuma, Arizona. This was done to keep dune buggy enthusiasts ignorant to what was actually being filmed. Blue Harvest hats and T-shirts were even made for the cast and crew.
This movie ties in directly with the Star Wars: The Clone Wars cartoon TV show. Originally, there wasn't going to be a movie, but George Lucas decided to combine the first four episodes into the theatrical release to get fans more excited about the series.