Parsing simple XML using NSXMLParser
http://www.iphonesdkarticles.com/2008/12/parsing-xml-files.html
http://wiki.cs.unh.edu/wiki/index.php/Parsing_XML_data_with_NSXMLParser
Parsing a bit more complicated XML using NSXMLParser
http://cagt.bu.edu/w/images/3/3f/ParseXML_sample_code_for_iphone_class_wiki