[Elling Polden]

The simplest way to kill a spear wielder is what we call the spear hunt.
Bind-Hanging guard-close-kill.
If he doesn't have a knife readily available he's toast once you've got the bind in place.

It doesn't matter much which bind you start up with; just push the spear aside, and close past the tip. If you have a shield, transfer controll to the shield. Otherwise, just grab his hand.
Then hit him wherever you can; If he goes low, the shoulder, if he goes high, the thigh or abdomen.
(Or stab him in the croch, for authenticy :P)
if he has a knife, keep your distance a a bit rather than steamroling into him, where he can slice you, and hit him with the tip of your sword.

Works like a charm.