The following resources provide more information and ideas on using poem lines for writing prompts and on writing workshops in the K-12 classroom:
Rose, where did you get that red?
Teaching Great Poetry to Children
by Kenneth Koch
Kenneth Koch's classic text Rose, Where Did You Get That Red? is an excellent place for teachers to start. Koch includes 10 great poems with complete explanation of how to use them as prompts for students as young as 3rd grade all the way through high school. Selections of student poems (from different age groups) follow the lesson plan. After the extensive explanation of the ten poems, Koch has an anthology section that is paralleled -- each entry has a brief description of a writing prompt that can be used with the poem.
The Teachers and Writers Handbook of Poetic Forms
edited by Ron Padgett
Teachers and Writers Collaborative
In honor of the 20th anniersary of the Teachers and Writers Collaborative The Handbook of Poetic Forms was published. This reference text with more than 75 forms from acrostics to villanelles is invaluable for teachers to use with students. A definition of the form is given, along with examples and ideas for how students might use this form of poetry.