Nmap - 3 part tutorial

A good one for beginners


Nmap Cheat Sheet: From Discovery to Exploits, 

Part 1: Introduction to Nmap
Part 2: Advance Port Scanning with Nmap And Custom Idle Scan
Part 3: Gathering Additional Information about Host and Network



Part-1
http://resources.infosecinstitute.com/nmap-cheat-sheet/

Part-2
http://resources.infosecinstitute.com/nmap-cheat-sheet-discovery-exploits-part-2-advance-port-scanning-nmap-custom-idle-scan/

Part-3
http://resources.infosecinstitute.com/nmap-cheat-sheet-discovery-exploits-part-3-gathering-additional-information-host-network-2/