Hi,
"Understanding Digita Signal Processing " by Richard Lyons is an excellent book for learning fundamentas of DSP.
Also "Scientists and Engineer's Guide to DSP " by Streven Smith is also an excelent book. This book is available freely on the net , goto www.dspguide.com !!!!!
I think, E.C. Ifeachor, B.W. Jervis, Digital Signal Processing: A Practical Approach, Second Edition, is quite a good place to start, its pretty easy to understand