Drug Links
Importing Drugs for Personal Use 

References
Controlled Substances Schedules (List) for 4 digit DEA code and Schedule.  I, II, IV etc.
Index of Brand and Generic Drugs
Index of Generic to Brand Drugs

Drug Descriptions Controls (limited List)
Drug Information Fact Sheets from FDA USA
Drug Information - a MEDLINEplus guide to over 9,000 medications
National Drug Code  USA

Agencies

Food and Drug Administration, USA
Drug Enforcement Administration

Organizations

American Pharmaceutical Association (Pharmacists)