The last issue of Mothering Magazine mentioned that co-sleeping and breastfeeding work together are the best combo as the mother and infant get into the same sleep rhythms.

quote:

Helen Ball, Senior Lecturer in Anthropology and director of the Parent-Infant Sleep Lab at Durham University, UK, discovered some significant differences between these two groups in research published in 2004 and 2005. Ball's observations were consistent with the observations of previous sleep-lab studies in regard to mother-infant bed-sharing behaviors. Significant differences were found, however, between formula and breastfed infants. Breastfeeding mothers shared a bed with their infants in a characteristic manner that provides several safety benefits. For example, their sleep positions are oriented to one another, and they experience synchronous arousal during sleep; that is, they wake up spontaneously at the same time for feedings. Formula-feeding mothers, on the other hand, shared a bed in a more variable and thus unpredictable manner, with possible negative consequences for infant safety.

From: Who Wants to Sleep Alone?
Issue 149 - July/August 2008
by Peggy O'Mara, Editor and Publisher

Try a search on Mothering.com for articles about "cosleep", this one is also quite good:

Breastfeeding & Bedsharing Still Useful (and Important) after All These Years
By James J. McKenna
Issue 114 September/October 2002