On a related note, I found this ebook ("Mindfulness in Plain English") an interesting read, clearing misconceptions about meditation and how it is related to mindfulness.
I loved it, as while this book was written by a Buddhist monk, apart from an odd reference here and there, the book is a "manual" first and foremost. It describes the mechanics of mindfulness meditation, rather than the Buddhist spiritual basis for it. It doesn't make any promises of supernatural results, and in general is a reasonably painless read for atheists or people who otherwise don't share the authors beliefs. The only mentions of Buddhism is for historical context.
In a similar vein, I'd recommend Gil Fronsdal's "Introduction to meditation" series of podcasts: http://www.audiodharma.org/series/1/talk/1762/
They're a great companion to Mindfulness in Plain English, and they're also largely religion free and no-nonsense.