I suspect using the advice here will be beyond many, and will probably not stay secure all that long, but it's a starting point.
Personally I'm in 2 minds about the whole PRISM issue, in that I rather expect the US (and to a lesser degree, UK) governments to be somewhat malign, yet at the same time they need to monitor what's going on. As much as anything, the issue is one of denial and lying about surveillance, rather than just advertising that it was going to happen. Most people are much less fussed about privacy than the somewhat geeky, anarchistic individuals that I occasionally like to talk with. From the lack of public reaction over the revelations so far I'd say that having been bought & sold over Facebook and google use, most ordinary people simply don't care at all.