[cflsystems]

Don't do search for products within category. Go to the categories list and click on the product number or go to the category you want to do the sort for and click on the product tab.
This will give you a list of product assigned to the category.
If you have more than X products the position field is text field to enter number into. If you have less than X products there is no text field for position - instead there is a drag/drop icon - just drag the products to change the order. X is the number of products to show on one page.