This is a really interesting interview with Ann Wright on Radio 4's Saturday Live programme, who accompanied in Colombia with Peace Brigades International. She gives a really great explanation about what accompaniment is and what you can get out of it as a volunteer. She's taking in the context of Colombia, but it's equally applicable to accompaniment in Guatemala. You can listen to it here.  Here's the intro from the BBC Saturday Live blog (shame they couldn't spell Colombia :-)).

"What makes a 60-year-old woman quit a comfortable life in London to become a human shield? For Ann Wright it meant giving her the opportunity to move in a completely different direction. Her retirement has taken her to Columbia and the West Bank where she has worked as a political protector, a kind of human shield, for groups such as Peace Brigades International."

You can find more information about accompaniment in general here, and how to become an accompanier with GSN specifically here.