More information about SAX in general, SAX 2.0 and SAX for Java in particular, is available at the SAX project on SourceForge. The definitive source for DOM information is the W3C DOM pages, although if you're not used to reading specs it can be slightly heavy going.
Freely available parsers you can use with Arabica
There's SAX and DOM coverage, generally Java focussed, in pretty much all XML books these days, although sadly most of it is rubbish. My current favourite is XML In A Nutshell by Harold & Means, published by O'Reilly.. There are two other XML books I particularly like, David Megginson's Imperfect XML (although its subtitle is poor and misleading) and Elliotte Rusty Harold's Effective XML, both published by Addison Wesley. Imperfect XML is strategic, Effective XML is tactical. You need them both.