Courtesy a little bird, it’s possible to download Firefox 3.0 already, though it hasn’t been announced yet.
The latest public download is RC3:
but if you remove rc3 from the URL, you get:
which is a valid URL. (So much for security by obscurity.) Enjoy your early start on Download Day! (Tip o’ the hat to Dil.)
Update: Or not. The version string in the -3.0 version is the same as the one in the RC3 version about box. Oh well.