There is no way in SQL 2000 - as it does not support any DMV's introduced in sql server 2005.
Your best bet is to use an AUDIT trace or run server side trace.
Note: depending on what you are capturing, it will be resource intensive and might end up filling up your disk space as well.
EDIT:
@rhughes
Refer to this para in the link :
To achieve a fine-grained approach to these types of auditing, you'll need to turn to Server-Side Traces. SQL Server has long provided the ability to trace activity for debugging and performance-monitoring purposes. You can also use Server-Side Traces to monitor security-related activity. Unlike C2 auditing, traces aren't persistent. If you restart SQL Server, the trace is lost and you must recreate it. Another difference between C2 auditing and traces is that you can start and stop a trace without restarting the database service. Traces are extremely configurable; you can choose exactly which events to audit and what information about each event to record.