This article on Unlimited Potential, an Arizonan group that helps immigrants to the US (presumably mostly Spanish speakers) learn English, funded primarily by grants, describes how they are making a difference in their community through language education. As a lawyer, I'm used to the idea of spending a certain portion of my time working pro bono providing legal services to those who otherwise could not afford them and it is interesting to see how the concept is implemented in other industries, and the language-learning industry in particular.
With resources available online, it seems to me that it would be trivially easy to enhance language education to groups such as those targeted by Unlimited Potential simply by providing them to access to computers with an internet connection and a webcam. You could easily get them on websites like Livemocha.com where they can learn for free with the help of native speakers. Public libraries seem like an obvious resource for this, with the only problem being the silence typically demanded by libraries. At my local library, for instance, computers are sitting in a sort of main area where you wouldn't be able to practice pronunciation or anything like that out loud.
A more interesting question, I think, is how can those companies whose core resources are not free - websites like LingQ or one of the big boys like RosettaStone - use what they have to help the disadvantaged. Could LingQ find some way to reasonably manage a pro bono tutoring service? The trick would be making sure the students actually deserve pro bono service. Could RosettaStone provide their software to disadvantaged groups? The trick there would be to make sure their donated or discounted software didn't end up back on the market.
Poking around a few websites and a few rudimentary Google searches don't seem to what, if anything, such companies are doing in this regard, so if any one has any examples I'd love to hear about them.