It depends on what level you want. If you want to know all edits that are made and what they did, you won't get that without turning SQL logging upto 5. Obviously this needs to be done before you want to monitor the user and also, this generates some rather large log files so you don't want this on for long.
If you just want to know what records in the system where they were the last person to edit them, you need to state which tables you're interested in. You can do a select from the company table, address, phone, communication (via the comm_link table, cases, opportunity, quotes, orders to see where their user ID is in the updateddate column.
Out of the box, Sage CRM provides no record level audit feature. There is a Journal table although I'm not sure if it was in 5.8 as we have no customers on that version now as it is way out of date. I think with 5.8 you're only option is the SQL logging but that is no use if you needed it yesterday.
Lee
