As I do not have any personal experience with this topic, I am
just listing some links below.
Making
it Meaningful: A Basic Guide to Breastfeeding Prematures. By
Cheryle G. Levitt (from Parents Place).
Remember: breastmilk is especially important for preemies--much
more so than full-term babies. Many hospitals provide breastmilk
for preemies from their milk bank if the mother is not willing to
provide it herself. But milk for the milk bank is not as good as
milk from mommy (even when the infant has to be tube-fed), because
it has to be pasteurized (out of fear of transmitting infectious
diseases), which kills the valuable antibodies
that help keep the baby healthy.
See also my page on breastfeeding preemies.