i saw a few mods that when a unit fired, a bunch on bullets came out instead of one. How is this done?

You modify the weapon behaviour to be valkyrie-like. Use "attack 3x3 cell" or something.
Then go to the unit attack iscript and find the line that says "attackwith1" and copy it as many times as you wish.

Spread can be achieved by having a missile sprite set to "Attack Target 3x3 Area". This'll cause them to choose a location offset from the target by a certain distance, which changes with each shot ( i.e., this is what the Valkyrie's Halo Rockets do ) .
To have a unit fire multiple shots at once, you copy and paste their attack opcode in their attack animation however many times desired, possibly with waits in between. Similarly, setting a factor of 2 in the weapons.dat will cause two projectiles to fire per opcode ( though 3 or higher do the same as 1 ) .

so what will i look for if i wanted to change the terran missile turret's attack to the spread shot?

darn! should of put that in my first post!

For the Terran Missile Turret to shoot two randomly-landing missiles:

Go to its weapon, the Lockdown Missiles. Look for "Weapon Behaviour" or "Flies to Target." Change that to "Attack 3x3 Area" (or something along the lines of that). Set the "Factor" value below the "Damage" value to 2.

You're finished! (This follows EzDay's second part of his tip.)

thanks!
BTW: the mod is going excellent so far

That may not be the kind of attack he means. He may mean the kind of attack where the unit fires shots at multiple angles at once, with the shots all going straight. I've seen it done in at least one mod. It involves using an attack with splash damage and that doesn't follow the target. In the iscript, it does multiple attacks, turning a different angle between each attack.

I've done that quite a few times, SF, usually with Firebats (I did so also in my NGGYU mod, if you want to check it out: Mod Projects forum). I think I tried doing that with Lurkers too once, but I can't remember if it worked or not.

It does. I've made lurkers that fire in all directions. It's lulzy.

Yeah, that's how you do it. The command used to turn is turncwise and turnccwise. You may think these commands need waits to go with them, but they do not. You'd accomplish the spead by using turnc(c)wise followed by an attackwith. Stack these commands until you achieve the desired effect. *trots off to find his Iscript file for BoB*

He means the type of attack like a "bunch of bullets", so it's note referring to many directions, necessarily.

Well, also you can try to play with the "launch angle" in the entry "Longbolt Missile" from the weapons.dat. That'll make the missiles to take nice trays before they hit. also yo can make the Missile Turret to get the Ground Weapon, they change the Iscript.bin and make the Turret attack with both weapons to the air in the AirAttkRpt animation (and then adding the new weapon to the Turret).