Apparently, Goku will reach his Super Saiyan form in "Dragonball Evolution", the live-action adaptation of Japanese popular manga. Exposing the possible spoiler for the first time was Dragonball the Movie which obtained a picture of the transformed Goku from an unnamed source.
In the picture which can be seen via ComicBookMovie, it is exposed that Goku might have been transformed into one of his "Super Saiyan" forms, in which he turns to be what seems like a giant ape. Still, Dragonball the Movie noted that it is unclear whether the image is the finished product of the transformation or not.
In the original series, Goku has been described to be the only Saiyan to achieve all the Saiyan transformations and is able to transform into a gigantic ape called an Oozaru. His transformation into a Super Saiyan takes place after being overcome with rage by the murder of Krillin. Starting from then on, he achieves every single advanced level of Super Saiyan which changes his appearance and enhances his abilities.
"Dragonball" is based on the popular Japanese manga from Akira Toriyama and resolves around Goku who becomes the Earth protector from the invading alien rogues. Directed by James Wong, it stars Justin Chatwin as Goku and is supported by the likes of Emmy Rossum, Chow Yun-Fat and many others. This 20th Century Fox film is set for April 10, 2009 U.S. release.