¡Colorín Colorado! — A wealth of information and ideas for teachers who work with ELLs, based on best practices for all students. Includes links to many other valuable resources as well.
Elementary English Language Learners — Strategies and resources applicable to ELLs at all grade levels, not just elementary
Newcomers at Grade Level and Beyond — Resources focused on secondary ELLs, but they can be applicable to all grade levels. Includes several video resources.
Seidlitz Education - Giving the Gift of Academic Language — A collaborative website featuring articles by prominent educators in the ESL field.
The Comprehensible Classroom — Includes valuable resources for language teachers. While some are specific to Spanish teachers, they are applicable and adaptable to ESL.
Tips for ELLs — This website is for all things teaching but this link will take you to the section with specific skills for ELLs.