History/Data Change File Approach

I need to record in a table:
Who, When, What Field and New Value of Fields
When changes occur to an existing record.

The purpose is for users to occassionally view the changes. They'll want to be able to see the history of the record - who changed what and when.

I figured I'd add the needed code to the stored procedure that's doing the update for the record.

When the stored procedure is called to do the update, the PK and parameters are sent.

The SP could first retain the current state of the record from the disk,
then do the update, then "spin" thru the fields comparing the record state prior to the update and after. Differences could be parsed to a "Changes string" and in the end, this string is saved in a history record along with a few other fields:

Name, DateTime, Changes

FK to Changed Record: some int value
Name: Joe Blow
Date: 1/1/05 12:02pm
Changes: Severity: 23 Project: Everest Assigned Lab: 204

How does the above approach sound?

Is there a better way you'd suggest?

Any sample code for a system that spins thru the fields comparing 1 temporary record with another looking for changes?

Thanks,

Peter