  We study chargino production e^+ e^- -> chi^+_1 chi^-_1 and the subsequent
leptonic decay chi^-_1\to chi^0_1 e^- nu_e including the complete spin
correlations between production and decay. We work out the advantages of
polarizing the e^+ and e^- beams. We study in detail the polarized cross
sections, the angular distribution and the forward--backward asymmetry of the
decay electron. They can be used to determine the sneutrino mass
m_{\tilde{\nu}_e}.
