TMACalicious

- Given Arnold Schwarzenegger's $15 million salary and his total of 700 words of dialog, that translates to $21,429 per word.
ie: "Hasta la vista, baby" cost $85,716!!!
- Most of Edward Furlong's voice had to be re-dubbed by Furlong again in post-production because it changed during shooting. His young voice is left intact only in the scene where he and T800 are talking about why people cry, because James Cameron wanted it to sound dramatic and thought it was better if left intact.
- Production took sufficiently long that Edward Furlong visibly aged during the shoot - he is clearly much younger in the desert, for instance, than in other scenes. His voice began to break and had to be pitched to one level in post-production.
- Linda Hamilton's twin sister, Leslie Hamilton Gearren was used as a double in scenes involving two "Sarah Connors" (i.e., when the T1000 was imitating her), and in a scene not in the theatrical release (but on the DVD) as a mirror image of Linda.
- The sound used for Arnold Schwarzenegger's shotgun is actually two cannons! lol

- The effect of the T-1000 freezing and breaking up was achieved through prosthetics attached to an amputee and with Robert Patrick's real limbs buried underneath the set.
- The "forced medication" scene (Special Edition only) had to be re-shot several times because actor Ken Gibbel wouldn't hit Linda Hamilton properly with his nightstick. The scene was very physically demanding and Hamilton was furious with Gibbel because he repeatedly botched it. She got her revenge in a later scene where she beats Gibbel with a broken off broom handle - the blows are for real.

- The Minigun used in the Cyberdyne scene was so heavy that Arnold Schwarzenegger was in fact the only person on stage that could carry the gun.

- Robert Patrick mimicked the head movements of the American bald eagle for his role as T-1000.
There's heaps more at http://www.imdb.com/title/tt0103064/trivia but i found the ones above were the ones that caught my eye.