Can't find the USPS shipping module!

I'm customizing my Zen cart (latest 1.5 version) and setting up my products/shipping. I have been all over the Zen cart website and read everything about the USPS module--just one problem. There was no USPS module in the modules folder. I even download a new copy of Zen cart (1.5 again) and still, no USPS module. So, I downloaded the "ZenCart USPS Shipping Module (RateV4 and IntlRateV2 API)", followed the instructions, and still no USPS module showing--I can't install it if I can't see it. Please help!

From whatsnew_1.5.0.html file in the zencart 1.5 docs folder:

USPS module removed from core in favor of being an addon, due to the volatility of frequent changes made by USPS. The addon is available in the Free Addons section of the Zen Cart website.

and from changed_files-v1-5-0.html:

DELETED Files (since release of v1.3.9)
/includes/languages/english/modules/shipping/usps.php