The International Labour Organization (ILO) and the World Bank both provide data on labour on their websites.
ILO -- The LO provides a number of free databases which can be accessed online. These include a searchable database on total and economically active population, employment, unemployment, etc. These databases provide time series and a selection of data. They are available at the country level and downloads can be created for multiple countries, multiple data elements and multiple years. Links to each of the available databases is at https://www.ilo.org/ilostat/faces/wcnav_defaultSelection . ILO also provides other data on request in digital format. The list of these databases is at http://www.ilo.org/global/statistics-and-databases/lang--en/index.htm . A list of free publications, which also include data is available at http://www.ilo.org/stat/lang--en/index.htm
World Bank -- The World Bank provides labour data in time series on its subscription data base World Development Indicators data base. You can get the data for the latest year for a single country from links on http://data.worldbank.org/topic/labor-and-social-protection .
United Nations -- Data on the labour indicators related to the Millennium Development Goals is available at http://unstats.un.org/unsd/mi/mi_goals.asp .