  In this paper we define an action of the Weyl group on the quiver varieties
$M_{m,\grl}(d,v)$ with generic $(m,\grl)$. To do it we describe a set of
generators of the projective ring of a quiver variety. We also prove
connectness for the smooth quiver variety $M(d,v)$ and normality for $M_0(d,v)$
in the case of a quiver of finite type and $d-v$ a regular weight.
