Mother’s milk is considered best for all babies but especially so for premature babies. These babies are at high risk for infections and mothers milk being rich in antibodies can be extremely beneficial. Some premature babies may not be able to nurse depending on their gestational age but they can be easily fed expressed breast milk with the help of nasogastric tubes.

I found some very informative articles on this subject online.

http://www.babycenter.com/0_breastfeeding-premature-babies_8480.bc

http://www.nbci.ca/index.php?option=com_content&id=70:breastfeeding-the-premature-baby&Itemid=17