'''Web sites'''

* ''http://xprogramming.com/'' (supersedes http://www.armaties.com/Practices/PracLeadin.htm)
* ''http://extremeprogramming.org''
* ''http://industrialxp.org/''
* ''http://MenloInstitute.com/'' (an XP mentoring company) MenloInstitute
* ''http://www.xispe.com.br/'' (a Brazilian (Portuguese language) XP wiki)
* ''http://c-sharpcorner.com/Code/2004/Feb/XtremeProgramming.asp'' A condensed Definition and Guide
* ''http://xpexchange.net/'' hosted by ManfredLange, XP info in both English and German

'''Web discussion groups'''

* ''http://groups.yahoo.com/group/extremeprogramming/''

'''Usenet'''

* ''news:comp.software.extreme-programming''

'''Publications'''

* CppReport published KentBecksChangeCostXpArticle.
* XP Testing Without XP: Taking Advantage of Agile Testing Practices (http://methodsandtools.com/archive/archive.php?id=2)
** This article describes how to use techniques from extreme programming for teams that have not implemented XP

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I couldn't resist but share this amazingly funny link. Forgot to mention that it does have something serious to say.   
* http://www.softwarereality.com/rumours/story032.jsp
** (see the whole http://www.softwarereality.com for details