I like O'Reilly for all books concerning Linux/Unix/Net.

Try:http://www.oreilly.com/catalog/learnredhatentlnx/inx.html and you can also try some basic free online howtos concerning installation and/or first_steps into RH4

RedHat5 isn't finished yet, so don't touch it. This stuff is only for longtime Linuxers and L-Devs...