There are literally dozens of data-bases covering US trade, multinational corporations, jobs, revenues, balance of trade with various countries in the BEA data sets, most of which are pretty easy to understand and access. See, particularly, See, US Dept. of Commerce, Bureau of Economic Analysis (BEA), Operations of Multinational Companies,
http://www.bea.gov/international/di1usdbal.htm, Industry detail (includes all industries), Position on a historical-cost basis, total financial flows without current-cost adjustment, and income without current-cost adjustment, 2005-2009| XLS
The most responsive estimate I have for you based upon this data is for MNCs, which employ abut 20 percent of the US workforce. The BEA says U.S.-based multinationals have shed about 2 million jobs since 2007, creating 1.3 million offshore.
Tell me specifically what you're looking for with regard to outsourcing, and maybe I have already crunched the numbers. I've found a good approach is to do a net trade deficit approach and convert that into employment figures (jobs gains and losses) in various industries. To do that, you can cross-reference with US Dept. of Labor Bureau of Labor Statistics (BLS) data. I've already done it for the Indian IT-Business Process Outsourcing sector, and the results might surprise you. The net current impact for Trade in Services with India is very small, about .1 percent in IT, because overall the US enjoys a sizable surplus in trade in services (a global net surplus of about $150 billion a year) and the current Q1 2010 trade deficit with India in the IT subsector is quite small (about $191 million (1), which equates to less than 2000 F/T positions in a 3.6 million US Information sector workforce). The biggest problem is not in Services, but in Trade in Goods, particularly manufacturing, and the deficit in manufactured goods with China is the single primary trade source that leads to U.S. job losses, with Mexico, Japan, and Germany following. The U.S. trade deficit in goods worldwide is on the way to a $600 billion deficit in 2010, which equates to 6-9 million U.S. jobs.
The bottom-line finding is that the single largest contributor to US jobs losses in the last decade has been layoffs and offshoring jobs by U.S.-based Multinational Corporations, which have been laying off Americans at a rate twice that of other corporations in this country. The U.S.-based MNCs have eliminated about 2 million U.S. positions since the current recession started in late 2007, creating about 1.3 million positions offshore.
(1) See, BEA,
http://www.bea.gov/international/bp_web/simple.cfm?anon=514770&table_id=10&area_id=37, data for US-India trade in goods and services, Table 12.