Due to a security bug affecting the Linux builds, there will be is a second Release Candidate for Firefox 3.6. According to Mozilla Links, “…Mozilla was considering January 19 for Firefox 3.6 release if the bug didn’t prove to be severe enough. So, final release date will most likely be January 26th…”
If all goes well and there are no further issues we can likely expect the final release of Firefox 3.6 on January 26th. This would be only about 3-months after the revised release date or 3-months earlier than the original planned release date.