We describe new combinatorial methods for constructing an explicit free
resolution of Z by ZG-modules when G is a group of fractions of a monoid where
enough least common multiples exist (``locally Gaussian monoid''), and,
therefore, for computing the homology of G. Our constructions apply in
particular to all Artin groups of finite Coxeter type, so, as a corollary, they
give new ways of computing the homology of these groups