There are several volunteer opportunities available in and around Xela [1], as there’s plenty of work to be done in Guatemala’s impoverished Western Highlands [2]. Any of the town’s language schools [3] can help you get plugged in to volunteer projects.
A particularly helpful organization for volunteer opportunities is EntreMundos (El Espacio, 6a Calle 7-31 Zona 1, tel. 5606-9070 or 7761-2179, www.entremundos.org [4]), which publishes a widely available free publication (EntreMundos) and has several resources on its website, including a database with contact information and descriptions for more than 150 NGOs in Xela [1] and vicinity.
Links:
[1] http://www.moon.com/destinations/guatemala/the-western-highlands/quetzaltenango
[2] http://www.moon.com/destinations/guatemala/the-western-highlands
[3] http://www.moon.com/destinations/guatemala/the-western-highlands/quetzaltenango/language-schools
[4] http://www.entremundos.org