The November 2008 issue of Poetry features a nice, full-color photo section on visual poetry. You can read Geof Huth's commentary on Poetry's website, but for the full visual imagery, you've got to get your hands on a copy.
"Few visual poems these days function as poems do. Instead, they encompass a wide range of verbo-visual creations that focus on the textual materiality of language. The form includes poems written as mathematical equations, collage poems, xerographic pieces that include no words but concentrate on the meaning that has built up within the shapes of letters, and even asemic writings in invented scripts created to mean through shape rather than word. Visual poetry is written for the eye, but its methods and intentions, even in those works most limited in their verbal content, are always poetic, always compelling the reader forward into the transformative power of language, always entranced by—and entrancing through—the text that is before us." (pictured: "jHegaf" by Geof Huth)