The Federal Government gathers a number of statistics relating to labor and employment, including Industries at a Glance, Unemployment and Occupation. For Employment, look at the Employment by Occupation links, as well as the Job Openings and Labor Turnover Surveys. For Earnings, the Wages by Area and Occupation is a useful dataset, as well as the Employee Benefits set.
Many of these are also available through the Federal Reserve Bank of St. Louis's FRED data interface. Population, Employment and Labor Markets information is available here, in the form of searchable graphs which can be manipulated to show various elements.
Search these three databases to find the best scholarly articles relating to all aspects of human resources management, as well as articles from trade, popular and news sources.
The Human Resources database from Vital Law (linked below) is a slightly different type of database. The content is written exclusively for subscribers, and includes a range of different types of items, from HR Manager's "Toolkit" to news items to legal analysis.
The W.E. Upjohn Institute is a private, nonprofit, nonpartisan, independent research organization devoted to investigating the causes and effects of unemployment.