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
;)
The only truly secure system is one that is powered off, cast in a block of concrete and sealed in a lead-lined room with armed guards.- Gene Spafford 
Nmap 5.00 Is out!