Tool to monitor database data
This solution does not require triggers but requires setup and causes a performance hit if you enable it for all tables.

Auditing has been built into Oracle for many releases.  There is an article here which goes into some detail.
Basically, you turn it on, tune it for what level of detail you want and the output is available as a dba view or as XML.

Check the system parameter AUDIT TRAIL, it sounds like you want the fine grained auditing available from 9i onwards so you can access the SQL_BIND and SQL_TEXT.

There is an SCN number so you can flashback to the state of the data when the change was made.

Keep in mind that there is a performance hit for all this. You must have the hardware and resources available if this is a production system.