The Amiga as it was known in its greatest form was a computer manufactured by Commodore after the Commodore 64. The series of Amiga computers was known as the Commodore Amiga line. The Amiga line was light years ahead of the competition, offering true stereo sound during the time of the infamous PC Speaker, and arcade-like graphics when PC graphics were blocky. It also featured one of the first (if not the first, not sure about that) true multi-tasking OS, known as Workbench (Now known as Amiga OS).
Its capabilities were due to its use of custom chips for different operations (seperate Graphics & Audio chips, etc).
Commodore went bankrupt (due to poor business decisions, and the PC hardware was finally catching up) and Amiga was seperated from the Commodore name. It was bought by Escom, and the latest Amiga models were re-released without the Commodore badging. Eventually Escom went bankrupt and Amiga has been bought by several companies since, including Gateway. It is now independant, known as Amiga Inc. and there are new Amiga Computers being built on G3 / G4 hardware. Amiga OS 4 is under development, and whilst there are not many companies still developing software for the platform, there is still quite a bit of interest from hobbyists, etc.
Hope that clarifies everything for you. That's a bit of the basic history of Amiga.
