You can manage users, sessions, processes, and terminal servers by using command-line utilities:

for w2k8/w2k8-r2: http://technet.microsoft.com/en-us/library/cc725766(WS.10).aspx

 

Command Description
Change Changes Remote Desktop Session Host (RD Session Host) server settings for logons, COM port mappings, and install mode.
Change logon Enables or disables logons from client sessions on an RD Session Host server, or displays current logon status.
Change port Lists or changes the COM port mappings to be compatible with MS-DOS applications.
Change user Changes the install mode for the RD Session Host server.
Chglogon Enables or disables logons from client sessions on an RD Session Host server, or displays current logon status.
Chgport Lists or changes the COM port mappings to be compatible with MS-DOS applications.
Chgusr Changes the install mode for the RD Session Host server.
Flattemp Enables or disables flat temporary folders.
Logoff Logs off a user from a session on an RD Session Host server and deletes the session from the server.
Msg Sends a message to a user on an RD Session Host server.
Mstsc Creates connections to RD Session Host servers or other remote computers.
Qappsrv Displays a list of all RD Session Host servers on the network.
Qprocess Displays information about processes that are running on an RD Session Host server.
Query Displays information about processes, sessions, and RD Session Host servers.
Query process Displays information about processes that are running on an RD Session Host server.
Query session Displays information about sessions on an RD Session Host server.
Query termserver Displays a list of all RD Session Host servers on the network.
Query user Displays information about user sessions on an RD Session Host server.
Quser Displays information about user sessions on an RD Session Host server.
Qwinsta Displays information about sessions on an RD Session Host server.
Rdpsign Enables you to digitally sign a Remote Desktop Protocol (.rdp) file.
Reset session Enables you to reset (delete) a session on an RD Session Host server.
Rwinsta Enables you to reset (delete) a session on an RD Session Host server.
Shadow Enables you to remotely control an active session of another user on an RD Session Host server.
Tscon Connects to another session on an RD Session Host server.
Tsdiscon Disconnects a session from an RD Session Host server.
Tskill Ends a process running in a session on an RD Session Host server.
Tsprof Copies the Remote Desktop Services user configuration information from one user to another.

Tips and tricks:

To query and list the sessions on the remote session, you could use QUser.exe or QWinsta:

C:>QUERY USER [username | sessionname | sessionid] [/SERVER:servername]

QWinsta is little different and better. It has more features and options. It comes with all flavors of Windows:

C:>qwinsta /?
Display information about Terminal Sessions.

QUERY SESSION [sessionname | username | sessionid]
[/SERVER:servername] [/MODE] [/FLOW] [/CONNECT] [/COUNTER]

Logoff command kicks off (logging off) the specified remote session:

C:>logoff /?
Terminates a session.

LOGOFF [sessionname | sessionid] [/SERVER:servername] [/V]

RWinsta has same parameters and does same thing as log off command. It simply means Reset WINdows STAtion:

C:>RWinsta /?
Reset the session subsytem hardware and software to known initial values.

RESET SESSION {sessionname | sessionid} [/SERVER:servername] [/V]