MS Releases free port Logger
Called "Port Reporter" MS released a tool to log port activity on new generation OS platforms. It runs as a service in the background and logs access to ports and can profile usage.
Check it out here for the executable.
Quote:
The Port Reporter tool logs TCP and UDP port activity. The tool is a small program that runs as a service on a computer that is running Windows Server 2003, Windows XP, or Windows 2000.
On Windows Server 2003 and on Windows XP-based computers, the service can log the following information:
The ports that are used
The processes that use the port
Whether a process is a service
The modules that a process loaded
The user accounts that run a process
Full Overview