  Using the tadpole improved clover Wilson quark action on coarse anisotropic
lattices, the $\pi\pi$ scattering length in the I=2 channel is calculated
within quenched approximation. We show that such a calculation is feasible
using small lattices on small computers provided that the finite volume and
finite lattice spacing errors are under control. Our results are extrapolated
towards the chiral, infinite volume and continuum limit. Comparisons of our
results with previous lattice results from JLQCD collaboration, the new results
from E865 experiment, and the results from Chiral Perturbation Theory are made.
Good agreements are found.
