Edit Nov 22 2006: On the Official GWT Blog:
After a couple weeks of fixing all the issues our developer community has so diligently reported in the issue tracker, we are happy to announce the official release of Google Web Toolkit 1.2 today.
As we mentioned when we released the 1.2 Release Candidate, you can now develop and debug with GWT on Mac OS X in addition to Linux and Windows. We are pretty proud of this particular feature because GWT is now about as "platform independent" as you can get: develop on Windows, Linux or Mac OS X and deploy to IE, Firefox, Safari and Opera on any platform, without any special cases in your code. (If you want a bit more detail about our implementation of Mac OS X support, our release nomenclature and other tidbits, this recent InfoQ interview may interest you.)
We also have already talked about how much faster the 1.2 hosted mode debugging environment is. And it is. If you've ever found yourself dropping to the command line using only the GWT compiler because hosted mode was too slow, you really should check out 1.2. Refreshes in hosted mode are almost instantaneous, and hosted mode lets you actually debug your code, which is nice...
The rest of the article, here.