The hint: how to download / export Picasa web album back to your Iphoto
But here is the solution I've found and I want to share it with others and wish I can make this post sticky.
Well, you need 4 things:
1. FireFox browser - http://www.mozilla.com/firefox
2. Greasemonkey add-on - http://www.greasespot.net/
3. Greasemonkey script - http://userscripts.org/scripts/show/15418
4. DownThemAll addon
After installing the two add-ons, restarting the browser and adding the script, go to the album you want to download, click on the "Init Download Links" button from the top of the page, select DownThemAll/DownThemAll in the contextual menu and type "imgdl=1" in the Additional filters box.
Macbook Air, just kidding:-)) Just Macbook, Mac OS X (10.5.2)