Liquor Licenses: Some states posts a database that lets you look up who holds a liquor license; links to these databases are available through SearchSystems.net. If that doesn't work, contact the relevant state's liquor authority and ask.
Liquor Laws: Liquor license laws from all states are compiled in the CCH Liquor Control Law Reporter and summarized in the DISCUS Summary of State Alcohol Laws & Regulations by the Distilled Spirits Council of the United States. Otherwise, look in the statutory code for the state and municipality in question.
Liquor Liability Law (LexisNexis) discusses the civil liability of "tavern owners, social hosts, employers, and others, for negligent service of alcohol to intoxicated persons and minors. The ABA publishes The Little Red Book of Wine Law.