The latest packaged releases are available at http://www.xmlpull.org/ and the latest source (if you want to be on the cutting edge) can now be obtained now from anonymous CVS at:
cvs -d :pserver:anonymous@cvs.xmlpull.org:/l/extreme/cvspub login CVS password: cvsanon cvs -d :pserver:anonymous@cvs.xmlpull.org:/l/extreme/cvspub co xmlpull-api-v1
Send them to XMLPULL mailing list.