since I m searching about piece of codes to replace the "default" picasa web album interface, I found this web site, which is a very nice collection of templates links and live sample :

http://www.paulvanroekel.nl/picasawebalbums/

There are several sections, one for picasawebalbums when you have your own host
and another to add templates directly in picasa.

As my strategy is rather to use Picasa as a storage space and the api to get access to pictures, I m more interesting in the Picasa Web album interface alternative