For hitchhikers Argentina can be divided into two parts. The north, which is pretty okay to hitchhike, and the south, which is a complete disaster, especially compared to its neighbour Chile. map24 is in Portuguese but has information about the whole of South America. A normal map is pretty expensive, but there is a road map containing many countries of South America for something like 10 pesos. In Argentina it´s normal to ask the people filling tanks at gas stations to ask people for you! If you´re a foreigner, do mention it! As a Dutch guy it seems to be a lot easier to get rides.