Multiple Attacks - Spellcasting?

[Benben]

If you have multiple attacks (BAB 6+), you can still only cast one spell (except for free-action spells like feather fall) during your turn. So if you choose the full-attack option, you are unable to cast a spell (but you get two melee/ranged attacks). Correct?

Yes. In general you get the choice to attack or cast a spell. Spells being the rule breakers that they are have way to many exceptions.

--If you have multiple attacks, (BAB 6+), and you choose the full-attack option, you cannot cast a spell and make a melee/ranged attack. Correct?

Correct.

--If you are hasted, you can only cast one spell (not two). The spell cast costs a standard action, so then you have a partial action to do something else. Correct?

D&D 3.5 In 3.5 with haste you are allowed one extra attack roll or can move your standard movement.

D&D 3.0 You get a partial action from haste, which allows you to move, or attack, or cast a spell.