The Legacy System Migration Workbench (LSMW) is a tool that supports data migration from legacy systems (non-SAP systems) to SAP systems. It is a cross-platform component of the SAP system.
BDC (Batch Data Communication) is used to transfer large amount of data that is available in electronic form. It uses the normal SAP transaction codes to transfer the data.
BDC requires ABAP Coding LSMW requires less coding. A proficient an functional consultant can upload the master data in to R/3 system without ABAP Developer. This is the primary difference between LSMW and BDC
you can access the following links for LSMW.
http://help.sap.com/saphelp_erp2005vp/helpdata/en/7a/5e3d38faba11d1b40f006094b944c8/frameset.htm
