The level I am looking to begin with is more of an adult level whose actual English skills are varied, but most are fairly poor.

I would need to know where you live and what age/level you are teaching, but without that information all I can do is tell you to try some of the large book stores or go to amazon.com. At Amazon, look at the publisher that you like and find there site.

I am a bilingual teacher and in my campus in Texas we use Avenues and Open Court from Hampton-Brown as our ESL/Bilingual components. They are both in English; Avenues is easier and Open court harder. It depends on the level of English proficiency of your students. This website might help you http://members.aol.com/adrmoser/esl.html

What kind of program do you want to offer? Do you want to have a program that teaches specific English skills and follows a grammar-based curriculum, or do you want to create a "tutorial" environment where students can come for assistance with their other classwork and develop their English skills at the time they're needed in other classes? If you want the former, I suggest using Oxford textbooks. They are by far my favorite. If you want to have the latter kind of program, you'll need a variety of textbooks (but not an entire class set) that address grammar basics (try a few Grammar in Use books and don't let the kids write in them!) as well as writing skills. You could add a few bilingual dictionaries, picture dictionaries and graded readers (for times when kids show up with nothing to do) to your library as well. This way you'll have the resources you need to help the students in every subject.

Your district may have an agreement to only buy textbooks from one publisher. If this is the case, you have to abide by their rules. In the end it means cheaper books for you, so you kind of win.

I teach high school ESL and I am using the Shining Star series by Pearson-Longman. They are appropriate for middle school as well. The texts come in five different levels: Newcomer, Introductory, and A, B, and C. I have Level B. The whole package has student textbooks, workbooks, and ancillary materials such as audio CDs, CD-ROM, videotape, assessment, and transparencies.

I like how the series integrates texts from all different disciplines. So far this year we've had historical fiction, science texts, and an excerpt from a young adult novel. Shining Star also helps you to teach grammar, spelling, and pronunciation. I'm happy with it and may order another level with my Title III funds this year.

Check out the website at: http://www.longman.com/ae/shiningstar/

For teaching language arts to english learners or anyone who has "missed" the boat in some ways when it comes to reading, the reading intervention called "Language!" is awesome. It includes sections for English learners in every lesson. Our ESL teacher is using "High Point" which is for English acquisition and also literacy.