I’ve recently started meditating, and came across this excellent introduction and manual to meditation, Mindfulness in Plain English which I discovered via Reddit. It is a superb introduction to meditation, and even better, the website offers up the text in web, PDF and ePub (iBooks) formats. For free!
This along with How To Meditate are both excellent introductions to the topic. No mystical mumbo-jumbo, just straightforward information with some history and technique.
If you are an iPhone user, be sure to check out the Lotus Bud meditation app.