how to file w2 form electronically

The Social Security Administration allows employers to electronically file W2 forms through their Business Services Online website http://www.ssa.gov/bso/bsowelcome.htm.   This site requires a specific type of file which  can be generated using W2 efiling software.   I would suggest looking into W2 Mate software.  This W2 efiling program will generate your electronic filing submission.