Here is a page of links to Argentine net art: http://www.martagonzalezobras.com.ar/pagweb.htm . The page is put together by Marta Gonzales. It contains links to work from 1995 to the present. A lot of compelling work here I have not seen before.
Also, here is a site of visual and other experimental poetry by the late Argentine poet Edgardo Antonio Vigo (1927 - 1997): http://www.eavigo.com.ar . There is an essay by the Uruguayan poet Clemente Padin about Vigo at http://www.thing.net/~grist/l&d/vigo/vigocp.htm
The eavigo.com.ar site was put together by the people at http://www.vorticeargentina.com.ar . This is an organization in Argentina that deals with visual poetry of all types.