Barring any "show-stopper issues" during the testing process, security and stability support for Mozilla Firefox 1.5 will expire on May 30.
The open-source group expects to ship the last Firefox 1.5 version on May 30 with an auto-update mechanism to migrate users to Firefox 2.
According to a post on the moz.dev.planning list, release candidate builds were pushed out to the "beta" channel on May 30 for a final round of testing.
We will be monitoring user feedback in the next few days, and if it doesn't uncover any show-stopper issues we will release official builds to all our users next week, Wednesday (5/30).
Firefox 1.5 support was due to expire on April 24 but this was pushed back a few weeks for an an additional Firefox 1.5.0.x release that incorporates the ability to accurately offer the user a chance to perform a major update (1.5 -> 2.0).
On May 30, users can also expect a Firefox 2.0 security and stability update.