You can create custom formatters for CCK Fields. The code is pretty simple.
This doesn't remove the extranious wrapper divs that cck creates by default, tho. To remove those I'm also using a modified content-field.tpl.php file. Read more »
I have two content type with different date fields that I needed to combine in a view, and sort that view by date. One type had a single date range that was precise to the day, and the other had complex recurring date ranges precise to the minute.
My view choked on the recurring ranges and output a line for every recurrence, but I only wanted the next upcoming or the last item.
I created a computed field in both cck types that evened out those values to become a common single value field for easier sorting.