Tools

• Expat (www.jclark.com/xml/expat.html)
  Written in C (ported to other languages), used by LIBWWW, Apache, Netscape, DSD, ...
• XML4J (www.alphaworks.ibm.com/tech/xml)
  From alphaWorks, in Java, based on Apache Xerces, supports DOM and SAX
• + 1000 others...

Editors

• Xeena (www.alphaWorks.ibm.com/tech/xeena)
  From alphaWorks, in Java, with tree-view syntax directed editing
• XMLSpy (www.xmlspy.com)
  Popular, but not free :-(
• + 1000 others...

Browsers

• Netscape Navigator 6 and Internet Explorer 5
  XML parsing and validation, rendering with XSL and CSS, script access via DOM
  IE is leading... :-(

  
  [More info: www.xmlsoftware.com has a comprehensive list of XML tools]