This sounds like a great endeavor.  I have been to South America as a volunteer but did not leverage my professional skills - at least not much.

Having said that, I would be that most of the NGO have business/systems analysis needs and you might be able help out that way if those organizations are headquartered in the country of your choice.  Another option is doing general computer/software training and help which many organizations need in the field.  When I was in Peru - I did a number of small projects for the local office of the organization I worked with such as: troubleshooting their PCs, creating templates for their document needs, teaching staff the finer points of applications such as Word, created a small MS Access DB & UI for one of their data tracking needs, etc.

There are also organizations looking for volunteers to work with kids to teach computers, business skills, etc.

Good luck to you!

I would love to hear what you guys end up doing?

- Adrian