I know nothing about Guatemala except that my best friend in college lived there and he introduced me to masa which is delicious. Wouldn't surprise me if Guatemalan food is a really healthy alternative to ordinary Western cuisine, I wonder if they grow that non-sweet corn in the U.S.? (google guatemala masa). See below some of this may not be useful since it seems you are not so much in the boondocks.
I have a friend who did this in Cambodia. I remember he got Apple to donate computers (this is one reason why not using open source hardware may have a good point, it counts as CSR (Corporate Social Responsibility) for a manufacturer to do so). It was for an orphanage he created, and the idea was to educate the next generation of leaders. Also he started a newspaper, probably also had Macs I forget.This was over a decade ago. Point being, they had to hire two armed guards so things wouldn't be stolen and I believe one guard was killed. FYI.
Getting locals who will carry it on, and talking to (global) missionary group as other posters mentioned are good ideas. I believe Hope Worldwide was a group he worked with for this charity.
Using open source may be cheaper and may help jump start an industry even if you had a university (need to connect them to the Net possibly) and local people who are enthusiastic.
You may be able to get the World Bank to help you, I know they did a dollar matching program for building rural schools (villageleap) of which hundreds were built.
Power and telecommunications may be a big issue. I'm sorry I don't have data for you but you know it is not first world. Maybe there are no phones and power? I remember one original idea was to have a networked school be a hub for the community, don't know how it worked in the end but I do know one thing they did was have a wifi equipped motorbike travel among rural schools and pick up messages. Useful for medical care.. Also the geography etc. makes you wonder about can you get a line of site to an access point, can you get wind power, etc. Of course the top priority for a community might not be computer education. Maybe power to cleanse drinking water, or communications to notify a doctor they need to get a helicopter somewhere. Getting X-rays sent to a specialist hospital was one thing we did but you don't need that.
On the other hand if it is the Labor de Falla that is 17 nautical miles from Santiago, then it is just a suburb not in the boondocks over the horizon from wifi. Possibly you could even get support from some place like Microsoft or IBM, if you say you are going to start training locals in computer science from a young age. Apparently Google discovered a mother load of such talent in Viet Nam just the other day (on /. today). Maybe that is your goal.
Anyway, figure out what your goal is, and don't spend all your time on the technical side. The key to making these kind of projects happen is getting the parts together, putting your own time in to monitoring it daily with someone on the ground, and being extremely tenacious and single-minded about getting this goal achieved. But you need to listen to people there and if there is no enthusiasm or problems maybe you need to ask what they want. There probably are a lot of smart people within 1 hour of your Guatemala location and not clear that they even need you. So I would focus on fund raising, enabling it, setting a mission and making sure it happens.
Just my 0.02, I clearly know nothing about the area. Best to be sure you accept there may be things you also don't know about it, and try to set smaller achievable goals for yourself. Maybe you can get a manufacturer to get you new equipment for free, that would be best. Imagine you are the student there. As for linux, yeah it would be nice but depending on the age group if they need to get a job in the city will it really help them? If you can make a success maybe you can then scale it up and make that part of your timeline for phase II.