I've done this one before, so it won't be a problem
Let's say you want to make a grenade spawn damaging fire upon exploding.
Open the grenade (or whatever projectile you're using) in IceCC, and add an imgol to spawn an unused sprite, which you will change to fire graphics using DatEdit.
Now open the iscript of the sprite you're using for the fire. Change it to look something like this:
CODE
"XSprite"init:
playfram X
domissiledmg
wait X
playfram Y
domissiledmg
;use whatever frames you want, change the wait and the number of playfram/domissiledmg to suit your timing needs
goto "XSprite"death
"XSprite"death
wait 1
end
And that's pretty well it. If you have problems with any of this, let me know.