We study the distributed infrastructures required for location-independent communication between migrating agents. These infrastructures are problematic: different applications may have very different patterns of migration and communication, and require different performance and robustness properties; algorithms must be designed with these in mind. To study this problem we introduce an agent programming language - Nomadic Pict. It is designed to allow infrastructure algorithms to be expressed as clearly as possible, as translations from a high-level language to a low level. The levels are based on rigorously-defined process calculi, they provide sharp levels of abstraction. In this paper we describe the language and use it to develop an infrastructure for an example application. The language and examples have been implemented; we conclude with a description of the compiler and runtime.