Kate,
My suggestion is to first look through this book- there are a lot of great ideas, tips, and resources that teachers in the ESL Field from all levels have posted to share with other teachers.

I would also do a search using the Boolean phrase of ESL Lessons for Kindergartners and elementary students- you will definitely find a ton of sites that give out free downloadable/printable activities to use with your students.

Yanni Zack