Transparent Material

How do you make transparent substances in blender? As to make it look like glass or something along those lines.

I use Blender 2.41, if that makes any difference.

shading (f5) materials button

mirror transp tab, turn on ray transp tab, move some sliders

scene button (f10), render tab, make sure RAY is on

Don’t forget to turn down alpha.

a ha… it was the raytransp that I needed to turn on.

Alright, thanks.