  The recent progress in embedding inflation in string theory has made it clear
that the problem of moduli stabilization cannot be ignored in this context. In
many models a special role is played by the volume modulus, which is modified
in the presence of mobile branes. The challenge is to stabilize this modified
volume while keeping the inflaton mass small compared to the Hubble parameter.
It is then crucial to know not only how the volume modulus is modified, but
also to have control over the dependence of the potential on the inflaton
field. We address these questions within a simple setting: toroidal N=1 type
IIB orientifolds. We calculate corrections to the superpotential and show how
the holomorphic dependence on the properly modified volume modulus arises. The
potential then explicitly involves the inflaton, leaving room for lowering the
inflaton mass through moderate fine-tuning of flux quantum numbers.
