Qouted from: http://nmap.org/5/
"Insecure.Org is pleased to announce the immediate, free availability of
the Nmap Security Scanner version 5.00 from http://nmap.org/
This is the first stable release since 4.76 (last September), and the
first major release since the 4.50 release in 2007.
Dozens of development releases led up to this."
I really hope I do not have to explain what this NMAP