As I’ve mentioned before, I think most teachers are much more likely to be engaged by blogs instead of something like Twitter because it’s more “within in their experience” — it’s like reading articles.
Google has now made it a lot easier to introduce using an RSS Reader to people new to the concept by letting you create “bundles” of feeds that you can share with friends. So instead of needing to have people subscribe individually (or exporting an OPML file — I don’t even know what that means!), you can create a subscription list from your own list with a click of a button for them.
You can read in TechCrunch about how to do it — they also have a screenshot.