Mac only 
Last week Windows users got the joy of carrying Firefox 3 in their pockets, and today Mac users can do the same thing! Earlier today Portable Firefox 3.0 for Mac OS X was released, and with it you can carry your browser around with you from one Mac to another.
One of the things that I really like about Portable Firefox 3 for Mac over the Windows counterpart is that it asks whether you want to import your existing Firefox profile into the portable version (as seen in the screenshot above). It will copy over your entire profile including bookmarks, passwords, extensions, history, cookies, and more. Of course Windows users can manually do this with their version of Firefox Portable, but you have to know where your profile is located.
Before getting started with Portable Firefox you’ll want to ensure that there is plenty of space on your memory card or USB drive. For the Mac version they recommend at least 57MB, and the Windows version is about 77MB.
Get Portable Firefox 3.0 for Mac OS X
Get Portable Firefox 3.0 for Windows
This would be a pretty good option for those who are always using Macs, but unfortunately most people who use Macs are forced to use Windows PCs when they go over to their friends houses. But, if you copy your profile from your computer to a thumb drive and install portable Firefox for Mac and Windows onto the thumb drive you will be able to bring your profile with you wherever you go.
Yeah, what’s cool is that you can throw both on a USB drive so that you’re prepared no matter where you are. What would be cool, however, is if the two different developers teamed up to offer an all-in-one package that shares the profile between the two installations. Sure it might be twice as large in size as it needs to be, but the convenience would be well worth it.
Has anyone actually succeeded in getting Portable Firefox 3 to run???
If so, on what hardware and OS and how?
I have installed it on both a USB flash drive and a USB hard drive that were attached to a G4 running OS 10.5.3. when I go to launch it I see a while circle/slash and by clicking on it I get a message to the effect that the architecture is not supported, even though th information on the download said that it was a Universal Binary.
Any suggestions would be appreciated!
Where does it say that it’s a universal binary? I don’t see anything on the page that says that.