Just want to add that I've installed the GUI interface to nmap (nmapfe) and looks great and regarding the windoze version it has also one though for an older version of nmap but with "idle scan" option too and a good html compiled help for the users as well with instructions on how to install NmapServ for regular scans of the network.

I didnt know either of the idle scan meaning till Ive read this article, thanks.