Vectiva died sometime after February 2005 and has been replaced by a site full of ads. Mail me if anyone has a mirror, or it has a new location.

Vectiva has a set of tutorials covering the basics and some stuff on DirectInput. Each tutorial has a nice accompanying text so its not just source code you have to look at. Looks like they are working on a series so check back often.

Waybackmachine mirror (though no real content): Physics, DirectX