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I came across some nice TCP port query tools that do better testing than DOS telnet to port x and leave a hanging connection from Microsoft.

Port Query UI tool from Microsoft (This does include the Version 2 of the command line tool.)

Example output using default SQL Server test - SQL Browser service is off on this server, but SQL Service is live:
Starting portqry.exe -n blv31wdb01.corp.dm.local -e 1434 -p UDP ...
Querying target system called:
 blv31wdb01.corp.dm.local
Attempting to resolve name to IP address...
Name resolved to 10.11.7.26

querying...

UDP port 1434 (ms-sql-m service): NOT LISTENING
portqry.exe -n blv31wdb01.corp.dm.local -e 1434 -p UDP exits with return code 0x00000001.

=============================================

Starting portqry.exe -n blv31wdb01.corp.dm.local -e 1433 -p TCP ...
Querying target system called:
 blv31wdb01.corp.dm.local
Attempting to resolve name to IP address...
Name resolved to 10.11.7.26

querying...

TCP port 1433 (ms-sql-s service): LISTENING
portqry.exe -n blv31wdb01.corp.dm.local -e 1433 -p TCP exits with return code 0x00000000.

Port Reporter - This is a service that can capture port information and give nice statistics. It doesn't capture everything. Use wireshark for that. KB article on the tool: http://support.microsoft.com/?id=837243
Support webcast on it, Note:  Download only works.
A log parser tool for Port Reporter service is also available.

Overview (Note Copied from KB Article)
Port Reporter logs TCP and UDP port activity on a local Windows system. Port Reporter is a small application that runs as a service on Windows 2000, Windows XP, and Windows Server 2003.

On Windows XP and Windows Server 2003 this service is able to log which ports are used, which process is using the port, if the process is a service, which modules the process has loaded and which user account is running the process.

On Windows 2000 systems, this service is limited to logging which ports are used and when. In both cases the information that the service provides can be helpful for security purposes, troubleshooting scenarios, and profiling systems’ port usage.
-Chuck Lathrope