I found out how to make this awesome aiming system a while ago that i have no use for so ill tell you all about it. With this system you wont be able to move while you shoot and its not too acurate but thats okay.

Make the follwing items.
Cross Hair, Character(with a seperate aiming animation), and the desired projectile(bullets, missles etc.)

Now youll use simple flags to control the aiming.

When Flag 1 is on.

Character- change animation to aiming animation
Player 1- ignore control.
Look in direction of cross hairs.
Make cross hair reappear.

Upon pressing (any desired key)+ Flag 1 is on
Character- shoot projectile at (0,0) from Cross hair

Flag 1 is off

Player 1- restore control
cross hair- make invisible set position at (0,0) from character

Make sure that the cross hair is moved by a different player than the player that controls the character otherwise when the flag is on you wont be able to move the cross hair.

I would like credits in your game if you use this so DC mail if you use it.