If you develop DotNetNuke modules you have probably seen the letter searching functionality in some of the core admin grids.  This control makes it each to implement the same functionatlity but fixes several problems with the built in method:

• Uses Viewstate to handle letter click so you do not need to maintain two sets of code (one for query params and one for view state)
• Uses Events to notify you when the page has changed and you need to rebind the grid.

This control is royalty free so a developer just needs to purchase one license and can use it in all their modules.