Get the new release from: http://getfirefox.com/

Here's what's new in Firefox 1.0.4:

* Several security fixes. http://www.mozilla.org/projects/security/known-vulnerabilities.html
* Fix to DHTML errors encountered at some web sites.
For web developers, learn more here:
http://developer-test.mozilla.org/docs/Working_around_the_Firefox_1.0.3_DHTML_regression