Luiz,
try this link for all sorts of hydraulic calculation: http://www.lmnoeng.com/index.shtml
Also a very understandable book:
REA's: "The Fluid Mechanics and Dynamics Problem Solver"
If you are really into pipe work and would go deeper than the above I recommend:
Larock, Jeppson, Waters: "Hydraulics of Pipeline Systems"
Hope this helps!
TM

Many of the best references are out of print.  I would suggest Lyon's Valve Designer's Handbook, which is very readable and deals with many of the practical, rather than theoretical aspects of the subject.  The section on the subject is rather small, but there is a lot of other good information on other subjects in the book.

One of the best is "Fluid Transients" by Streeter & Wylie.  Most WH work these days is done with computer simulation of much of the principles described in this text book.  There are virtually 1000s of papers on WH.

Try Pressure Surges in Pipe & Duct Systems by Swaffield 7 Boldy ISBN 0-291-39796-4
Extracts of the authors book can be seen on the following site.
 http://www-interact.eng.cam.ac.uk/wh/index.html

Also Applied Hydraulic Transients Chaudry Van Nostrand, Fluid Transients in Pipelines D & L George and The British Hydromechanics Research Association technical papers.

Also look at www.aft.com and download their demo Fathom & Impulse software. Fathom is for steady state and Impulse for transient analysis.

I run Fathom and Impulse and have used it for many multipipe systems.

How about http://www.omega.com/techref/waterhammer.html ?

or a water hammer calculator at http://www.haywardindustrial.com/whc/ps01.htm