1) Spells that have a casting time of 1 standard action can be interrupted by attacking the caster or by any other means?
2) Any way of interrupting a ranged attack with a bow or a melee attack with a sword?
Interrupting as in stopping? Not normally. You can attempt a readied action upon being attacked, but even then it depends on your GM's willingness to allow "being chosen for an attack but before they swing" as a valid trigger.
Now, if you can do that and you kill the guy, then you've interrupted the attack. With spell casting, you can force a concentration check (and "the guy starts making spell casting motions" is a pretty solid readied action trigger) that may interrupt the casting.
Ready an action. Your readied action will "go off" just before the trigger.
In the case of a spellcaster, any damage you do will require a concentration check by the caster (in addition to any other the caster had to make for casting defensively, if he did that).
In the case of a bow attack or melee attack, if you succeed with sunder or disarm, you'll disrupt the attack (unless they can quickdraw a different weapon). If you trip, the attack will still come, but at a minus for prone attacker.