PBS's Frontline produced a four-hour documentary called "Drug Wars," an in-depth investigation of the social, political, and international effects of the War on Drugs over the past thirty years. The accompanying website includes transcripts of the documentary, along with a great deal of extra content, including access to primary sources.
The Office of National Drug Control Policy is ground zero in the federal government's efforts to win the War on Drugs. The ONDCP's website is the best starting point for an understanding of contemporary government policy on drugs.
The independent website called Drug War Facts has ugly web design and a clear political agenda—the site is skeptical about the usefulness of the War on Drugs. That said, the information provided here is conveniently sub-divided into useful categories and (in stark contrast to many pro-legalization websites) all claims here are carefully attributed to reputable sources. The site might be read as a sort of counterpoint to the pro-War on Drugs stance of the official ONDCP site.
National Geographic offers an online exhibit on the history of coffee. The section on "Coffee Legends" is particularly interesting; check out the Ethiopian legend about how a poor goatherd discovered coffee's magical properties after he noticed his goats "dancing from one coffee shrub to another."
The Yale Center for the Study of Globalization provides a nice, brief overview of tobacco's place in the history of the modern world.