Resolving data in hook_views_data
You can theme (you dont want to change the value stored in the DB, just change its displayed value) the view row value by using a template suggestion:


I prefer using a preprocessor function to do this on the field. This blog post covers how to do this for a specific view_name and field.

From the blogpost:


  There is an issue to let Drupal 7 and 8 themes implement a
  preprocess/process function per view as it is possible in Drupal 6,
  but it is in development (see issue).
  
  Until it is fixed there is a way to achieve that behaviour:


&lt;?php
/**
  * Generic preprocess that is still working on D7
  */
function MYTHEME_preprocess_views_view_fields(&amp;$vars) {
  if (isset($vars['view']-&gt;name)) {
    $function = __FUNCTION__ . '__' . $vars['view']-&gt;name . '__' . $vars['view']-&gt;current_display;

    if (function_exists($function)) {
     $function($vars);
    }
  }
}

/**
  * Then the specific preprocess that worked without the above code for D6
  */
function MYTHEME_preprocess_views_view_fields__VIEWNAME__DISPLAY(&amp;$vars) {
  // my specific preprocess code
}
?&gt;


There's also like views_custom_styles (sandbox project) and views_php which will let you do the same thing -- but for what you're asking (to my knowledge) you're gonna have to write code.

The preprocessor example I give is a clean solution re-using the Theme API (suggestions) and hooks.