Shoutbox

Hey,
I am making images in photoshop for a tshirt maker and he has told me that they cannot have the anti-alias applied where it blurs and blends the edges into the background to give a smoother effect.  He needs the picture/edges to be sharp for the special printer machine thing (screen printing).
How can I disable anti-alias when creating an image? or is there another format i can save in?

I have already asked and I cannot simply apply the sharpening filter in photoshop as this is not enough.

If anyone has any ideas or can suggest some things for me to try please let me know.

Thanks