rahulbatra recommends starting by reading the essay
"The Nature of Lisp." Here's a sample:

The enlightenment came instantaneously. One moment I understood nothing, and the next moment everything clicked into place. I've achieved nirvana. Dozens of times I heard Eric Raymond's statement quoted by different people: "Lisp is worth learning for the profound enlightenment experience you will have when you finally get it; that experience will make you a better programmer for the rest of your days, even if you never actually use Lisp itself a lot." I never understood this statement. I never believed it could be true. And finally, after all the pain, it made sense! There was more truth to it than I ever could have imagined. I've achieved an almost divine state of mind, an instantaneous enlightenment experience that turned my view of computer science on its head in less than a single second.

A few other resources:

• Loving Lisp, or the Savvy Programmer's Secret Weapon by Mark Watson. I haven't read it and don't know how good it is, but the e-book is available for free.
• Try Scheme - a web based Scheme console.
• Yet Another Scheme Tutorial
• howto-learn-scheme

Lisp alien logo by Conrad Barski, M.D.