I've helping with an adult ESL class at my church.   Anyone have any suggestions of materials or books that might be helpful in teaching adults with limited English skills?

For beginning level students, the Oxford Picture Dictionary (with teacher guide) and Betty Azar's Basic English Grammar are a pretty complete curriculum.  

http://www.paperbackswap.com/Basic-English-Grammar-Betty-Schrampfer-Azar/book/0133683176/

Teacher guide:

http://www.paperbackswap.com/Basic-English-Grammar-STACY-HAGEN-BETTY-AZAR/book/0132052156/

http://www.paperbackswap.com/New-Oxford-Picture-Dictionary-English/book/0194343553/ (it comes in one language or in other second languages= look around for what you need)

Teacher guide: http://www.paperbackswap.com/Oxford-Picture-Dictionary-Jayme-Adleson-Goldstein/book/0194740684/