Tested some of the samples and they are pretty smooth, you just need to install a one file (5.3mb)
Google on Tuesday released software called O3D to bring accelerated 3D graphics to browsers, a significant effort but not the only one to try to endow Web applications with some of the computing muscle that PC programs can use.
Google’s O3D lets browsers show accelerated 3D graphics such as this island scene.
O3D is a browser plug-in for Internet Explorer, Firefox, Safari, and Chrome that works on Windows, Mac OS X, and Linux, but Google hopes that eventually, the technology will be built directly into browsers. It provides an interface that lets developers’ Web-based JavaScript programs tap directly into a computer’s graphics chip, which could mean better games and other applications.
read the article here http://news.cnet.com/8301-17939_109-10224078-2.html?part=rss&tag=feed&subj=Webware
Google O3D page http://code.google.com/apis/o3d/..