Many teachers attempt small group instruction, only to be interrupted by the "independent" workers with questions. A 5th grade teacher in Dearborn, MI uses an easy idea to promote peers as a source of assistance.
On one of the white boards in the room, there is a two column chart. Any student who gets stuck while working independently can get out of their seat, go up to the board and write their name in the left column and their question or need in the right column. Other students who are working independently can glance at the board to see the questions. If there is a question they feel they can answer, they have permission to go to the student's desk. If the two students are able to solve the problem, the peer helper erases it from the board on the way back to his or her seat.
I was impressed with how smoothly this system worked in the classroom and I love that it elevated students to peer helpers. As an added bonus, the teacher gets to work with her small group without interruptions.