I am looking for resources on English language grammar to use with ESOL students. Any recommendations would be greatly appreciated

You could try:
OnestopEnglish - http://www.onestopenglish.com/ This website is a teacher's resource site organised and run by Macmillan Education in order to help EFL, ESL and ESOL teachers.

There is a also a section on our own subject directory providing links to a number of resources to support his area of the curriculum - http://www.rsc-sw-scotland.ac.uk/mmm_learning_resources/esol.htm