The following two books are an excellent starting point:
J.Gibson & J.Hunter "Victuallers' Licences Records for Family and Local Historians", 2nd ed, 1997.
S.Fowler "Researching Brewery and Publican Ancestors", 2003.
As noted up-thread, local directories are incredibly useful - especially when licensing records have not survived. Consult G.Shaw & A.Tipper "British Directories: a bibliography and guide to directories published in England and Wales 1850-1950 and Scotland 1773-1950", Leicester, 2nd ed, 1997 for comprehensive lists of every known directory published. Major local libraries and county archives tend to have good holdings.
I've found all the above to be immensely useful when tracing my publican ancestors.