KLOE prospects and preliminary results for Kl3 decay measurements

The KLOE experiment has been running since April 1999 at the DAFNE e+e- collider at a center of mass energy centered around the phi meson mass. The luminosity integrated up to September 2002 is about 500 pb-1 . Here we present the perspectives on the measurement of the V_{us} CKM-matrix element with the KLOE detector, using both charged and neutral kaon semileptonic decays.