If you are looking to get started, then I strongly second the recommendation that you get Mark Wilson's book.
Nicholas Einhorn has written one that is also good (and can be picked up for about £5 in lots of places). It's available under two different titles. See here:
http://www.talkmagic.co.uk/ftopic1578.p ... ht=einhorn
I got a copy in Borders three months ago.
The Mark Wilson one has the edge, but is slightly more expensive. You can get both for about £20 and there's enough for you to be practising for ages. See what you enjoy from those books before buying anything else.