Can anyone tell me how to add a clipping mask

right click on a layer and click "create clipping mask"

if you want to make a clipping mask with for a example a splatter brush, you have to make a new layer,
brush once with your splatter brush and hide that layer. then make a new layer, go to Image -> apply image, then
unhide your splatter brush layer and move with your mouse between those two layer while holding "Alt" until a symbol appears and click

ty
is this the same with gimp?

I dont know I never used gimp sry

ya all the pro GFx guys use cs4

i use cs3 find it better

ya just in general the photoshop series.. i personally use gimp also when im bored.. dont feel like paying $100 for cs