EDIT: The below was posted as my April Fool's joke, a little late. If you're arriving from Google or elsewhere and were hoping for serious updates on the SpaceX Falcon Heavy announcement, try this post instead for my serious reaction to the actual news.
So, there's been a lot of chatter the past week or so about the teaser video SpaceX put out, linked below.
That some element of the Falcon 9 Heavy (now apparently renamed Falcon Heavy, possibly because of the planned switch to a single Merlin 2 engine per core instead of 9 Merlin 1Cs sometime in the future) was going to be announced, and that a new launch site might be involved was also not unexpected (plans for a site at Vandenberg capable of processing the Falcon Heavy have been filed with EPA already, several months ago). However, new leaks (I can't cite sources yet) indicate that this may not be the entire extent of the "something big" coming!
New source inside SpaceX suggest that the Vandenberg facility is not the only new launch site SpaceX has been working on, nor is Falcon Heavy the only rocket being announced. In fact, SpaceX is planning to announce their new Thunderbird rocket, which is the implementation of their Falcon X and Falcon XX proposals. The cores for Thunderbird are in fact too large to be road-transported as Falcon is, so the new rockets will have to be built and launched from the same site. To this end, SpaceX has been constructing an underground Thunderbird construction, integration, and launch facility beneath Mr.Musk's personal island residence for several months, and the Falcon Heavy is to be the first vehicle to use it, with launch NET April 5, 2011. A leaked image of a model of the new site is depicted below, showing a generic rocket (SpaceX plans to offer the site to other users during periods of non-total use.) on the launch stand, with the launch site's water damping system and weather cover yet to retract to the launch position.
Of particular interest is the switch from horizontal integration as they are using at the Cape and the Vandenberg site filings to a vertical integration technique at the Musk Island site. This could be an indication that they plan to try for more manned launches, or increased competition with other launch providers like Arianespace who integrate vertically (payloads would thus not require redesign to be fitted onto Falcons or Thunderbirds launched from Musk Island). I meant to post this a few days ago, when more time remained before the launch, but I'll wait for the full announcement tomorrow with baited breath, and my best to the team preparing Falcon Heavy for its maiden flight, and the Thunderbird 1 vehicle for next Tuesday. FAB, guys.