Yup, photoshop almost exclusively for the redrawers and typesetters, and plain ol' text documents (with some "this line goes on this page in this bubble" shorthand) for translators and proofreaders.

Gimp, sadly, does not really work, since it doesn't represent .psd files the same way photoshop does. It's easier to sail the high seas than it is to get a Gimp workflow working. :(