Apt sources for deb-src packages in Etch

[Alejandro <alejandritox@ciudad.com.ar>]

Hi all,

I have Debian Etch and I have this in my /etc/apt/sources.list file:

deb http://ftp.us.debian.org/debian/ etch main contrib
deb http://security.debian.org/ etch/updates main contrib

But I need the deb-src sources (security and normal packages), I tried 
with  a pair of sources but they don't work....please can you send me 
some valid deb-src sources ??

And other question: what the difference if I use the word "etch" or 
"testing" in the sources ??? Any idea ??

Really thanks,

Alejandro