You can apply a formatter to the date field that will convert the current format to a more readable date format. To use a formatter create a function that will return the date, in this example dojo.date.locale.format is used to return the date in a format like August 14, 2007.
function formatDate(value){
var inputDate = new Date(value);
return dojo.date.locale.format(inputDate, {
selector: 'date',
datePattern: 'MMMM d, y'
});
}
Apply the formatter to the date field:
<th field="DATEFIELD" formatter="formatDate;">Date</th>
Take a look at the following sample in the help to see an example:http://help.arcgis.com/EN/webapi/javascript/arcgis/demos/fl/fl_paging.html