The Association for Borderlands Studies is an excellent portal to information about many international borderland regions. It also maintains lists of links and resources on specific regions, including the Mexico-US border.
The Torn Apart Project: This website uses digital technologies to map the significance of US Immigration and Cutoms Enforcement (ICE) detention centers. Volume I locates all ICE detention centers on a US map, and provides additional access points to alternative views of the ICE landscape, including information such as photographs and data. The Allies tab links to a directory of organizations providing various kinds of support to undocumented immigrants. Volume II digs deeper, tracing the financial context of ICE; who has funded and who has profited from this phenomenon, including the role of money, businesses, and politicians and government agencies.