Mirrorshades: the Cyberpunk Anthology, edited by Bruce Sterling, paperback ISBN: 0441533825. Out of print but easily found at used bookstores on and offline.

Many of the stories in this anthology would not be classified as cyberpunk by many readers and reviewers today, but these stories reflect the varied origins of the movement/genre. I've annotated the table of contents with information from Locus:

- Preface: Bruce Sterling
- The Gernsback Continuum: William Gibson (Universe 11, ed. Terry Carr, Doubleday, 1981)
- Snake-Eyes: Tom Maddox (Omni Apr ’86)
- Rock On: Pat Cadigan (Light Years and Dark, ed. Michael Bishop, Berkley, 1984)
- Tales of Houdini: Rudy Rucker (Elsewhere v1, ed. Terri Winding & Mark Allan Arnold, Ace, 1981)
- 400 Boys: Marc Laidlaw (Omni Nov ’83)
- Solstice: James Patrick Kelly (IASFM Jun ’85)
- Petra: Greg Bear (Omni Feb ’82 )
- Till Human Voices Wake Us: Lewis Shiner (F&SF May ’84)
- Freezone: John Shirley (Eclipse, John Shirley, Bluejay, 1985)
- Stone Lives: Paul Di Filippo (F&SF Aug ’85)
- Red Star, Winter Orbit: Bruce Sterling & William Gibson (Omni Jul ’83)
- Mozart in Mirrorshades: Bruce Sterling & Lewis Shiner (Omni Sep ’85)

You may read the preface, which is a discussion of the movement as well as the book, at http://www.cyberpunkproject.org/idb/mirrorshades_preface.html