Did he promise to veto? I don't remember that. I thought he sort of tiptoed around it in 2000. As his veto record shows, he's deferential to the Congress to a fault.
Yes, he did. He's threatened to veto only a few bills, most of them towards the conservative side, but he's never vetoed anything.
Also see my reply to supercat. He just asked the same question. My answer is in #253 or #254.