Creating and Using Groups~ This is a great article about how to form groups, assign tasks, and keep students accountable. Well-organized and useful! I found this after reading about Shelly Terrel work. It's a fantastic idea to balance group of students.
Group formative assessment of behavioral skills. This free poster is great for any small group work, whether it's used for pull-out groups or with cooperative groups in a classroom. Students are forced to rate themselves based on performance as a group.
Corkboard Connections: Cooperative Learning - More Than Group Work - Learn the difference between cooperative learning and group work, as well as strategies for fostering effective team discussions. (I like the "talking sticks" discussions!