CCK Field with two values?
Take a look at the CCK multi group options, which are only a part of CCK 3.0+. This functionality allows you to combine multiple base fields into one field grouping. See http://drupal.org/node/119102 for the long history on how this came about. 

I actually can't find good documentation on using it, as CCK 3.0 is still only in Alpha, so unfortunately you'll just have to play around with it some.

The other option is to write your own CCK field type, in which there is no issue creating multiple inputs for one field. The upshot is that you can definitely achieve this using your own custom field, the downsides are you are writing custom code (which is nice to avoid) and it's not as flexible as the multigroup options built into CCK 3.0