On Opportuntities we have the default "Next Steps" field, but it's not very long and we'd like to retain back history of the progress of a deal.  I've created a long text field "Sales Progress".  Here's what I'd like to do using a workflow trigger and field update:  Whenever a new entry is made in Next Steps, copy that entry over to Sales Progress and add it to the bottom (or top) of the existing text.  What would the formula look like?