Coin magic is a great field! Much of what you learn in coins will carry over into other fields as well, such as ball manipulation, ring magic, and sponges. Here are my suggestions for getting the best foundation in coin magic and why you need them!
Bobo's Modern Coin Magic: http://www.penguinmagic.com/p/535
If you haven't heard of this title yet, you definitely MUST have this. Much of what modern coin magic is now has come from this classic book. I admit there is a lot in here that I don't personally like, but in between all that is a whole world of amazing gems you WILL love!
In the beginning there were coins: http://www.penguinmagic.com/p/1581
Jay Noblezada goes into some great detail on this DVD showing you in person what a good coin magician looks like (but obviously he has cooler shades). This shouldn't replace your knowledge with bobo's but the learning process will be much easier on DVD.
Revolutionary Coin Magic:
This DVD isn't a full guide to performing sleight of hand. You will learn more hard-hitting tricks and sleights on the side, but how to incorporate them into the routines you're performing. Also check out Revolutionary Coin Magic 2.0 for more great sleights and tricks!
David Roth's Expert Coin Magic set:
Once you're ready with the basics of coin magic, you'll be taken into some more sleight of hand to accomplish different feats. This is a must have because many of the classics of magic are in these DVDs straight from the guy who popularized them.
David also performed an entire two hour lecture for us here at Penguin and demonstrated many of these must have routines. Check it out here: http://www.penguinmagic.com/p/2663