Here are some topics that you may want to consider and address with your co-collaborators:
(1) Are there any ownership issues you want to address up front? We recommend that you consider different Creative Commons licenses as an alternative to copyright. If your goal is primarily to create something beautiful or something interesting, then you might not be too concern about ownership rights. But you should make sure that you are on the same page with co-collaborators up front. You may want to address ownership questions pertaining to the poetry, the public performance of the song, and the recording of the song.
(2) Do you want to touch base at various points in the process? Do you expect to see or hear drafts if they are available? Or are primary artists (the poets, in most cases) comfortable waiting for the final product?
(3) Should poetry be kept in tact, or would the poet(s) be willing to accept edits for the sake of the song? If edits are acceptable, then to what extent? Minor edits only? Repetitions? Omissions?
(4) What kinds of deadlines do you want to set? Deadlines might not need to be specific, and they might be left open for amendment, but we at Ham Kicker will ask that some sort of timeline be set.
Let me know if you have questions: joe.robinson@hamkicker.com.