This organization, jointly operated by the UN and GATT, deals with international trade (particularly with developing and transitional countries). Besides details information on their mission and programs, they offer considerable data on-line (and even more is available on their CD-ROM products). Their COMTRADE database is "by far the most comprehensive source of trade statistics as it covers over 100 reporting countries with time series starting from 1963 (SITC1), 1978 (SITC2) or 1988 (SITC3 correlated to HS codes)." This data is available on a CD-ROM product. In addition, a subset of this data is available on-line. To quote, it has "only total imports or exports by countries for all product groups (3 digits level) of the Standard International Trade Classification Revision 3."
http://www.unicc.org/itc/Welcome.html