Two questions I recently couldn't find the answer to in the PHB: 1) Dual classing doesn't seem to have any level restrictions. That is, the Human could switch at any level. In fact, couldn't a Human Fighter switch at 1st level without having acquired any experience at all? 2) What level casters are Rangers and Paladins for their spells? Does a 9th level Ranger who just got himself a Magic Missile get 5 missiles? Obviously, cites in the books would be good if you know them.
1) It's up to the DM. Your example reeks of rules-abusing munchkinism. I'd most-likely impose some heavy penalties if a player tried it. 2)Gary told me that the character would be caster level 1 at the first level he gained spell casting ability, and it would increase by 1 for each level gained afterwards.
I concur with ScottyG. There are no btb rules on the first issue that I am aware of. I rule in my game that one must be at least 2nd level to switch and no more than 3 classes may ever be attained. As for the second, just as ScottyG said. I think that it is btb that the the first level a class attains spell casting ability (be it 1st or 9th), the caster level is 1st. I'll dig around for the official answer, if there is indeed one. Alternatively, you may find a swifter answer to your question over on the forums at http://www.dragonsfoot.org. If you are not a member yet, sign up, that site really rocks for getting pre-3.0 D&D questions answered.
