Western Union and Money gram are financial institutions that transfer money all over the world. For each operation they make, costumer has to pay for it. In fact, there is no Riba in this kind of operations and they are paid because they offer a service. Question: Is Halal or Haram to be a Western Union or Money gram agent offering there service and making money by the same way?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Working in money exchange to transfer money from place to place and charging for that is permissible.  You may also work as an agent for this transaction.  However, the condition for this exchange is that the ownership of the money should not be delayed as any delay between giving or receiving the money is considered Riba in Islam and it is forbidden. This is the ruling of "hand-to-hand" transactions.

Allah knows best.