Yesterday I looked into the Silverlight Toolkit for Windows Phone and I covered some of the controls that are included in the current build. One of the controls that might be a bit unusual to configure and get working is LongListSelector, which allows you to group items inside a list. With a regular ListBox, you can display data but there is no way to jump directly to an item set, and there is no way to group items.
Clumping Items Together
One of the best features of any phone is the ability to clump together large lists of items so that they become easier to sort through. Not every phone has this ability though, and it can be very frustrating for some phone owners who are just trying to go through their lists in the easiest ways possible.