This entry was published at least two years ago (originally posted on February 16, 2005). Since that time the information may have become outdated or my beliefs may have changed (in general, assume a more open and liberal current viewpoint). A fuller disclaimer is available.
Amazon has the full trailer for 
The Hitchhiker’s Guide to the Galaxy on their home page right now. It’s Flash-based and kind of small, but at least it’s there.
So far, things look promising.
Update: Waxy has a QT version.
I found this much higher-quality Quicktime trailer, that seems to be a copy of the internal workprint with time signatures and “Do Not Duplicate” warning. Oh, well!
“Shoot That Laserbeam (Re-Recorded)” by Army of Lovers from the album Army of Lovers (1991, 4:22).