Overriding ActiveRecord for timestamp insertion on UPDATE and INSERTS?

[eluser]TheFuteballer[/eluser]
We've recently run into a need for adding timestamps in our database at the row-level. I'm hoping I can avoid going and editing every update and insert command we've ever written to add the timestamp field entry.

Is there anyway I can safely override the ActiveRecord class to do this for me on every update and insert? Or ideas on best way to approach this?