Check out this tutorial. Or come back in 24 hours and I'll have updated this thread with instructions.
That guide is for Snow Leopard.
Not that I know of I'm afraid. Both the Applications folder and the dock access the same file for the image. You could try changing the background colour of the Applications folder to one that better compliments the text icons.
Thanks but it doesn't work for me even though I have Snow Leopard. I don't have the files on my computer that it says in the first couple steps.