BackTrack: Update Nmap installation

sudo su
wget http://nmap.org/dist/nmap-5.00.tar.bz2
bzip2 -cd nmap-5.00.tar.bz2 | tar xvf -
cd nmap-5.00
./configure
make
make install

To determine current version installed:
nmap -V

To determine last version, go to:
http://nmap.org/download.html