GNS3
http://www.gns3-labs.com/
http://www.networknotepad.com/index.htm
http://www.blindhog.net/
http://www.configureterminal.com/ccna-ccent-ccnp-ccvp-ccie-cisco-free-ebooks-study-guides/free-gns3-labs-training-resources/gns3-tutorial-pdf-documentation-install-configure-how-to-use-gns3.html
http://chikkis.blogspot.com/2009/05/cisco-voice-gns3-cme-startup.html
http://www.gns3.net/phpBB/topic242.html
Voice & VoIP
http://ccvp.org/
http://cisco.buzz.hu/
http://packetlife.net/