Managing dispatch in an open access environment is a new challenge facing independent transmission system operators who are mandated to provide a level playing field for all transmission users. Two issues are especially important viz; use-of-transmission-system charges and congestion management. This paper examines aspects of these issues with emphasis on the latter. Pool, bilateral and multilateral dispatch co-ordination are explored and mathematical models developed for each case. The practical case when all three modes coexist is discussed with respect to both forward and real time dispatch.