-- SQL Server 2005
EXEC SP_WHO          // details on who is logged in
GO

-- SQL Server 2008
EXEC SP_WHO2         // even more details
GO

-- Run as database owner to see ALL connected processes as well.

1.  -- SQL Server 2005 
2.  EXEC SP_WHO          // details on who is logged in 
3.  GO 
4.   
5.  -- SQL Server 2008 
6.  EXEC SP_WHO2         // even more details 
7.  GO 
8.   
9.  -- Run as database owner to see ALL connected processes as well. 

Message 3511 not found; No message file for product=NETWORK, facility=TNSMessage
3512 not found; No message file for product=NETWORK, facility=TNSMessage 3513 n
ot found; No message file for product=NETWORK, facility=TNSMessage 3509 not foun
d; No message file for product=NETWORK, facility=TNS

1.  Message 3511 not found; No message file for product=NETWORK, facility=TNSMessage 
2.  3512 not found; No message file for product=NETWORK, facility=TNSMessage 3513 n 
3.  ot found; No message file for product=NETWORK, facility=TNSMessage 3509 not foun 
4.  d; No message file for product=NETWORK, facility=TNS 

ol{margin:4px}

-- yields
995.
996.
997.
998.
999.
000.      <-- What's going on here then?
001.
002.

1.  ol{margin:4px} 
2.   
3.  -- yields 
4.  995. 
5.  996. 
6.  997. 
7.  998. 
8.  999. 
9.  000.      <-- What's going on here then? 
10.  001. 
11.  002.