750/625 meters per second for dumbfires/seekers. 600 mps for packhounds and 250 for torpedos.
Torpedos can definitely be dodged fairly easily. It is much more difficult to dodge seekers but still possible. If you have a fast manueverable ship, the best method (I’ve found) is to be travelling away from the launched missile with FAOff, then right about when the missile comes within 1km (depending on your speed) boost towards the missile at an accute angle. The problem with that is if you are in a position to dodge a missile launched by an NPC, he has most likely launched several others at you, so the odds are good that if you successfully dodge the first, you’re going to get hit by the next one.
Just my experience and I am by no means a combat expert, less so expert at dodging missiles.