sysprocesses
However, having being where you are, a 2 minute poll to that table is not adequate. It does not take 2 min to connect, change data and disconnect. Rather go with a server-side trace if you can, you'll catch every single login that occurs.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability