In the August 2004 edition of Windows magazine, Mark Minasi wrote an article on PortQry.exe, a windows command line tool for port scanning. I've been using nmap for years on linux, so I thought I would give portqry.exe a spin, since Microsoft is already on version 2 with this utility.
Even though PortQry.exe does scan ports, I think nmap is a better tool. I visited the nmap site and it appears that they have a version for windows, but it looks like to be more difficult to install than PortQry.exe.
Update 7 AUG 2004
Another article on portqry.exe.
Portqry isn't a unique tool. Nmap has been around for a while, and my Linux buddies like it. But the Windows versions of Nmap are cumbersome and involve lots of files and a necessary wizard for installations. In contrast, Portqry is just one 217KB file that takes up little space on my "useful tools" CD-ROM or my "stuff that's good to have around" USB keychain. Nmap performs a variety of tasks, but Portqry is just what I need, particularly when I want to find out whether an ISP's servers are up.