Operations Research Course ISC612 - Project material - Minimum Cost Flow problem

An excellent source of information is the book "Network flows: Theory, Algorithms, and Applications" by R.K. Ahuja, T.L. Magnanti and J.B. Orlin. Other books on network flows or combinatorial optimisation may also help. There is also a nice article (parts 1 and 2) about MinCostFlow algorithms on topcoder.com.