Mozilla

http://www.mozilla.org
XUL Granddaddy; runs on Mac OS, Linux, Solaris, FreeBSD, Irix, BeOS, HPUX, OS/2, BSD, and more

mozilla-xul Mailing List - Alternative Archive @ Gmane
Ask questions or share tips and tricks about Mozilla XUL.

Xul Tutorial @ Xul Planet
http://xulplanet.com/tutorials/xultu/
Neil Deakin's example-packed, no-fluff Xul workout

Xul Intro @ Mozilla
http://www.mozilla.org/xpfe/xptoolkit/overview.html
Beyond hairballs and spaghetti code: separate content, appearance, behavior and locale

Creating Applications with Mozilla Using XUL, CSS and Javascript
http://books.mozdev.org
O'Reilly's 500-page Xul thriller by David Boswell, Brian King, Ian Oeschger, Pete Collins, Eric Murphy (September 2002); all twelve chapters available for free in HTML under the Open Publication License; 1. Mozilla as Platform; 2. Getting Started; 3. XUL Elements and Features; 4. CSS in Mozilla Applications; 5. Scripting Mozilla; 6. Packaging and Installing Applications; 7. Extending the UI with XBL; 8. XPCOM; 9. XUL Templates; 10. RDF, RDF Tools, and the Content Model; 11. Localization; 12. Remote Applications

Xul Reference @ Mozilla
http://www.mozilla.org/xpfe/xulref/
All tags and attributes lined-up

Xul Reference @ Xul Planet
http://xulplanet.com/tutorials/xultu/elemref/
All tags and attributes illustrated

Xul Spec @ Mozilla
http://www.mozilla.org/projects/xul/xul.html
Xul spec under construction

Quick Reference @ Xul Planet
http://xulplanet.com/tutorials/xultu/elemref/quickref.html
All tags grouped

Mozilla XUL FAQ
http://www.xulplanet.com/tutorials/xulqa/

MozillaZine
http://www.mozillazine.org
Most Popular Mozilla XUL News Site

Mozilla News
http://www.mozillanews.org
Less Popular Mozilla XUL News Site

Komodo / Active State
http://www.activestate.com/Products/Komodo/ | http://aspn.activestate.com/ASPN/Mozilla
Dev Studio for Perl, Python, PHP, XSL/T and more

NewsMonster / Kevin A. Burton
http://newsmonster.org
News, weblog, and RSS aggregator that runs inside Mozilla 1.0 (Netscape 7.0 or greater) on OS X, Linux, or Windows and showcases the power of XUL and Java.

Mozilla XUL Apps @ mozdev.org
http://www.mozdev.org | http://www.mozdev.org/projects.html
Hosts over a hundred Moz XUL apps such as XULmine (XUL-based Minesweeper game), Jabberzilla (Jabber IM client for Mozilla), Mozoffice (Office productivity suite project) and many more.

Rapid Application Development with Mozilla
http://www.amazon.com/exec/obidos/ASIN/0131423436/
Xul thriller (November 2003) by Aussie Nigel McFarlane; 704 pages; Prentice Hall, ISBN: 0131423436

Creating Applications with Mozilla Using XUL, CSS and Javascript
http://www.oreilly.com/catalog/mozilla/ | http://www.amazon.com/exec/obidos/ASIN/0596000529/
O'Reilly Xul thriller (September 2002) by David Boswell, Brian King, Ian Oeschger, Pete Collins and Eric Murphy; 474 pages; ISBN: 0596000529

Essential Xul Programming
http://www.amazon.com/exec/obidos/ASIN/0471415804/
By Vaughn Bullard, Kevin Smith and Michael Daconta (July 2001); covers the whole Mozilla Xul machinery including CSS, XBL and RDF; 448 pages; John Wiley & Sons; ISBN: 0471415804

Mozilla XUL Links
Includes links to Mozilla XUL articles and much more

O'Reilly Mozilla DevCenter
http://www.oreillynet.com/mozilla/