Fallout can be buggy at times, so you may wish to download the patch. Click Here to visit Interplay's official site. You can also find demos, screensavers, and other goodies here.
If you want to know more about the Fallout world, Click here for the Fallout Bible. The Fallout Bible will explain many of the plot holes and backstories of the Fallout games. Do NOT download this if you have not finished Fallout, as these downloads are spoiler ridden.