After Picasa, another Google software (well at least Google-owned software) will be ported to Linux: Google Earth. From LinuxToday:
"Picasa, founded in 2001, was purchased by Google in July of 2004, and the photo management tool has seen some extensive use, albeit from Windows users. DiBona indicated that Google made a public committment to begin porting two applications to Linux about a year ago. The other application in this project is Google Earth. Picasa for Linux was announced first simply because it was finished first.
When asked if the additions to WINE would bootstrap Google Earth's porting progress, DiBona answered in the negative, explaining that Google Earth relied on Qt and GL libraries and code, so additional WINE support would not help. No timeline for that application's release was revealed at this time."
If these applications are succesful, Google will port other programs: Google Talk, SketchUp or maybe even Google Desktop.
Dave Kegel, who works at Google, wrote an interesting mail in the Wine developers group:
"Many people assume that when porting a Windows app to Linux using Wine, the best thing to do is link Winelib into the application to create a native Linux application. Not so! It's just as effective, and a heck of a lot easier, to run the same binary on both Windows and Wine. So that's what the Picasa team did. Picasa for Linux uses slightly different text messages, but the .exe file is identical for both Windows and Linux.
The Picasa for Linux team had a blast. It's not often you get to pour resources into a vital open source project to help ship a commercial application! We hope we get to do it again sometime soon, and we hope the results are good enough to encourage other companies to give Wine a try."
Many Linux users think Google should build native versions for their software, instead of using Wine, but if Wine becomes powerful enough to run (almost) any Windows software everyone will gain: more people will adopt Linux because they can use their favorite applications and companies will have a wider audience for their software.
Update: Google Earth for Linux has been released.