One of the best tools I've learned about is Quia. This is an exercise creator site. I HIGHLY recommend you check it out. You can get the 30 day free trial and if I hear from enough of you that you want to use it, we can purchase a group membership. Anyway, you can search a database of exercises created by teachers in various fields including ESL. It is so easy to use. You can create quizzes that are scored and reported to your email, you can create vocab review exercises, grammar review practice, games, quizzes, surveys, etc. Here is a link to a vocab review I made for Michelle's Vocab Development class this week. SO EASY - it took about 5 minutes!
I'm going to add links to other Online Exercise Creator sites I've learned about to the UCAELI Teacher Sites when I get a chance. It's really worth taking a few minutes to try some of these.