Penetration Testing: delving deeper

[Chris Benedict <chrisb () daemonnews org>]

Hi, I've been looking at security and penetration-testing for some 
time now and would like to get further into it.  I'd like to learn 
more about penetration-testing, forensics, techniques for network 
exploration/mapping, web application security and incedent handling. 
However I'm not really sure where to start, I looked at the OSSTMM and 
it was above my head.
At the moment I have a very limited budget and only a few spare 
low-end computers.  If it matters, I'm mainly running OpenBSD.  Are 
there any particular books or other media that I should take a look at?
Any thoughts or recommendations are welcomed and greatly appreciated.

-Chris Benedict