We present the study of spin and charge transport in nanostructures in the presence of spin-orbit (SO) interaction. Single band tight binding Hamiltonians for Elliot Yafet and Rashba SO interaction are derived. Using these tight binding Hamiltonians and spin resolved Landauer Büttiker formula, spin and charge transport is studied. Specifically numerical results are presented for a new method to perform magnetic scanning tunneling microscopy with non-magnetic tip but in the presence of Elliot Yafet SO interaction. The spin relaxation phenomena in two-dimensional electron gas in the presence of Rashba SO interaction are studied and contrary to naive expectation, it is shown that disorder helps to reduce spin relaxation.