This is all covered on Wikipedia under "Home video release"
Due to rights issues, the American pilot (94 minutes long) was not released in the United States home video market until 2007. The European pilot (116 minutes) had been released on VHS and laser disc years earlier: this alternate version of the pilot was aired in Europe as a stand-alone television movie. The European version is identical to the United States-aired version up until the last several scenes, when the killer of Laura Palmer is revealed. Both versions of the pilot are included in the Twin Peaks: Definitive Gold Box Edition DVD set, released in the US on 30 October 2007. Lynch was so pleased with the footage shot for the European ending that he later incorporated some of it into Cooper's dream sequences that aired in subsequent episodes.