Mozilla has released today the Major Update allowing Firefox 2.0.0.18 users to upgrade to Firefox 3.0.4.  Users should be offered the upgrade option in the next couple days. Alternatively, users can also get the update by selecting the Check For Updates option via the Help menu. Either way, users will be presented with a prompt similar to this:

• Later: Firefox will ask again in 24 hours
• Never: Decline the upgrade offer.  You may get another offer again in the future, but it won’t be for several weeks or months
• Get the new version: Upgrades to Firefox 3.0.4

As a reminder, the final release on the Firefox 2 branch, version 2.0.0.19 is schedule for release around December 16th. There may be one last major update offer sometime next year to move to the current Firefox 3 build.

Source: Mozilla Developer’s News