This has been a long time in the works but Official Picasa is out for Linux. They did it using WINE. Most people are on their case of doing a WINE port instead of a native port, but I think its cool that they’re supporting WINE development. I’m sure their contributions (either financial or code-wise) will help other applications that previously didn’t work under WINE.
Picassa itself isn’t the big deal here. There are plenty of open-source apps that I think are better with managing pictures. The big news is their support of WINE.