Nicolas Labarre has written a great article for his blog on visual culture on the subject of adapting poetry into comics.
http://culturevisuelle.org/essaysincomics/?p=72
Although the article is in French, Nicolas demonstrates his ideas through a series of his own adaptations of a single short poem by Emily Dickinson, the text of which he has kept in the original English.
As well as providing a much-needed overview of the development and present state of this practice, the article present some very insightful theories on the different strategies that have been used thus far by different cartoonists, including yours truly. After studying comics academically as a master’s student for almost three years now, I must say it is an odd and gratifying feeling to see my own work discussed in a scholarly tone.