Google Earth has an official version for Linux and it runs natively unlike Picasa, which uses WINE. But you wouldn’t know looking at Google Earth’s interface in Linux; it looks like an ugly WINE application. I’ve got a how-to if you haven’t yet installed Google Earth.
Google Earth uses the Qt toolkit, which is what the KDE environment is based on. But even in KDE, Google Earth will not take the system theme because its version of Qt is built-in instead of using system-wide library.