Help! Record logging

Hello,

I would like to setup a trigger to keep track of all changes done
onto the records of paticular tables. Basically, there would be two
identical tables such as, 'medications' and 'medications_log', when a
user inserts, updates or deletes a record I would like a copy to be
inserted into the log table. I already have audit information in the
medications table, so I only need to be able to copy the record over to
the log table.

The only other difficulty is how do I let the trigger know the ID of
the user deleting the record?

Thanks,
Edwin S. Ramirez