  We propose a new method to use gamma-ray bursts (GRBs) as an alternative
probe of the dark energy. By calibrating luminosity-variability and
luminosity-lag time relations at low redshift where distance-redshift relations
have been already determined from type Ia supernova (SNIa), GRBs at high
redshift can be used as a distance indicator. We investigate the potential
impact of future GRB data on determining the current matter density
$\Omega_{m}$ and the dark energy equation of state $w$ which is assumed to be
constant. We show that a combined analysis of a data set expected from the {\it
Swift} and the current SNIa data results in excellent determination of both
$\Omega_{m}$ and $w$.
