Due to diversity and quick dissemination of information, journals have a higher number of audience when compared with other information carriers. Nevertheless with the emerging new information technologies have contributed to the appeal and thriving of journals, Open Access Journals in particular. The present paper intends initially to discuss the open access movement that gave rise to the emergence of open access journals. It would then introduce modes of open access as well as the characteristics and definitions associated with OAJ. This would be followed up by a classification of OAJ along with their advantages. Means for financing such journals as well as directory of open access journals would be also discussed. Finally, the OAJ covered by ISI as well as those published by the top 20 countries who lead science production are presented