You can also find the ports that are open on your computer by use of GUI tools

Note: These tools will show you whatever ports are open or in use, but they are NOT scanning tools! If you want to have your computer scanned for open ports see this page instead (link will follow shortly).

Net Monitor v0.90

Nice, simple and free. It will show listening and connected ports and log them to any file you want.

A newer and not free version of this tool is now available by the name of NeoMonitor

You can download the tool from attachments given in this article.