Also available here:
http://www.zen-cart.com/index.php?main_page=product_contrib_info&&products_id=314
SVN available here:
http://google-checkout-zencart.googlecode.com/svn/trunk/
Next release: 1.45-beta1
Zip scheduled for August 27, 2007
Change Log history is here:
http://groups.google.com/group/google-checkout-for-zen-cart-mod-support/web/changelog-history
Possible feature changes and fixes in next mod version is indicated
on wishlist/known issues page:
http://groups.google.com/group/google-checkout-for-zen-cart-mod-support/web/wish-list-features-functionality